Bygenm S i a a * ” ge oe ee

| [AG COMPARATIVE ZOOLOGY,

VY. { AT HARVARD COLLEGE, CAMBRIDGE, MASS.

Founded by private subscription, in 1861.

RNADEARARAA ANN

No. IGS4,

FIGURES AND DESCRIPTIONS OF CANADIAN ORGANIC REMAINS.

|

A Wa aaa I.—FOSSILS from the base of the Trenton Group. By J. W. Sanam, bk Palzontologist of the Geological Survey of the United Kingdom. if: Sk

= IL—GRAPTOLITIDE# from ihe Lower Silurian. By Professor Tasces ts Hatt, Paleontologist of the State of New York.

“ TIL—CYSTIDE and ASTERIDEA. By E. Bituines. Genus CYCLO- Pe CYSTOIDES. By H. Brtines and J. W. Sautmr. Paleozoic ae Bivalve ENTOMOSTRACA. By T. R. Jones, Esq.,F.G.8.

“ TV.—CRINOIDE from the Lower Silurian. By E. Biturnes.

Decades I. and III. are published. Decade IV. will be published on the Ist of J une, ; and Penne II. in about six months.

FOR SALE BY ie

B. DAWSON & SON, 22 Great St. James Street, Montreal; A. H. ARMOUR & oe yt Toronto; JOHN WILEY, New York; HECTOR BOSSANGE & SON, Paris, Franters SAMPSON, LOW, SON & Co. Psuden, England.

Montreal, Ist May, 1859.

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Pibrary of the Museum COMPARATIVE ZOOLOGY,

AT HARVARD COLLEGE, CAMBRIDGE, MASS.

Founded by private subscription, in 1861.

No. J G38, UY

GEOLOGICAL SURVEY OF CANADA.

SIR W. EH. LOGAN, F.R.S., DIRECTOR.

FIGURES AND DESCRIPTIONS

OF

CANADIAN ORGANIC REMAINS.

DECADE II.

GRAPTOLITES OF THE QUEBEC GROUP.

BY

JAS MOR Ss OH Ant

MONTREAL: DAWSON BROTHERS. LONDON, NEW YORK, AND PARIS: BALLIERE.

1865.

7 es ad | Wa tie

; Re

Reine FA OC i.

The Graptolites of the Quebec group, which are the subject of the present Decade, were first discovered at Point Lévis in 1854, and were then confided for investigation and description to Professor JAMES Haut of Albany, the distinguished Palzeontologist of the Geological Survey of the State of New York. This was prior tu the appointment of Mr. E. BILiines as Palzeontologist to the Canadian Survey, in 1856. After a preliminary notice communicated by Professor Haut in 1855, extensive additions were made to the collection of Canadian Graptolites, which were placed in his hands; and in 1858 descriptions by him of nearly all the species here figured were published in the Report of Progress of the Geological Survey of Canada for 1857, but without illustrations. Figures of one of the species were however published in the Canadian Naturalist for June 1858; but various accidental difficulties having occurred in the preparation and engraving of the plates, the publication of the Decade has been delayed until the present time. |

It is to be remarked that although the name of Decade, under which Parts I, I11,,and Iv were published, is still retained, this monograph is illustrated by not less than twenty-three plates. These are all from excellent drawings by Mr. R. P. Wurrrietp of Albany. ‘Twenty-one of them were engraved on steel by Mr. James Dutuim of New York, and the remaining two were lithographed by Mr. F. J. Swinton of Albany.

W. EH. LOGAN. GEOLOGICAL Survey OFFICE, Montreal, December 1864.

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TABLE OF CONTENTS.

CHAPTER I. INTRODUCTION.

§ I. Nature and form of Graptolites; formerly known only in fragments; regarded by early writers as of vegetable origin; their reference to Cephalopoda by Wahlen- berg, Schlotheim, Geinitz, and Quenstedt, page 5.—Their first reference to Poly- piaria; the supposed affinity of Graptolites to the larve of Echinoderms, 6.—The name Graptolithus first established, 7—What forms are properly referable to the genus Graptolithus, 7-8.—Dendrograptus, its mode of growth, and gradations through Callograptus to Dictyonema, 10-12.—Forms of some Graptolites similar to the recent genus Crisia, 13.—Forms with diverging stipes, 14.—Doubly serrate forms (Diplograptus), 15.—Phyllograptus, Retiograptus, Retiolites, Rastrites, 16. Thamnograptus ; Inocaulis, and its affinities to Graptolites, 18.

§ II. The central or basal portions of Graptolites, 19.—The radicle or initial point, 19. —The funicle, 19.—The central disc, 20.

§ III. Nature and parts of the stipe, 21.—The solid axis, 21—The common canal, 23. —The cells, cellules, or calycles ; their form and mode of development, 24.—Their similarity to the recent genera of Hydroide, 25.—Cell-walls, their double appear- ance and structure, 27.—EHxcavated cells, 27.—Their internal structure, 28.—Cells in Retiolites. Apertures of cells in some species of Graptolites; in Dendrograp- tus, 29.—The cells of Dictyonema, 29, 30.—Ornaments of the test in different genera and species, 30, 32.

§ IV. Mode of reproduction and development in Graptolites, when first made known, 32.—Different forms of germs, and their reference to species, 34.—Reasons for sup- posing that the diprionidian forms always existed as simple stipes, 36.—Develop- ment of cells in different genera, 37.

§ V. Mode of existence, 38.—Simple or compound forms; floating or fixed forms, 39.

§ VI. General characters of the Graptolitide, 40.—The condition of specimens heretofore described. Genera and sub-genera proposed : reasons for and against retaining these, 40 —43.—Diplograptus, to what forms the term is properly applied, 44.—Peculiar characters of D. putillus, 44.—Biserrate forms which are properly separable from Diplograptus, 45.—The genus Retiolites, 46.—Differences observed between Huro- pean and American specimens, 47.—Retiograptus and other genera considered, 47-50.—Synopsis of the genera of Graptolitide, 50.

§ VII. Geological and geographical distribution of the Graptolitide in the rocks of Canada and the United States. Equivalency of the American graptolitic beds with those of Europe, 51.—Mr. Barrande’s opinion of the age of the graptolitic schists in Northern Europe and in Bohemia, The graptolitic beds in New York. Discovery

iV

TABLE OF CONTENTS.

of a Graptolite in the Potsdam sandstone. The graptolitic beds of Canada, 52

Graptolites of the Utica slate and the Hudson-River formation, 53—54.—Table showing the vertical distribution of the genera of the family of Graptolitide, 55.— Table showing the geological distribution of the species of Graptolitide in Canada

and the United States, 56-58.

§ VIII. Historical notice of the genus Graptolithus, 59 - 64.

CHAPTER II.

§ I. Synopsis of the species of Graptolitide from the Quebec group, described in this

Memoir, 65 - 68.

§ Il. Descriptions of the species of Graptolitide illustrated in this Memoir, under the

following genera:

GRAPTOLMEHUS .«e\e!ajs\k.c/s cles sis/aie sieve ue here mis Geka aust toveiterenrie ale tevelsy«' ais (leis(e(e[staie aes TET OGRA DUS tors jciscoxey els 010) cjereiercle clove a ayeeroRete RAG Hes. Anwae sae » o.eieieere tee CLIMACOGRAPTUS ....... ehicreleteierodete ae Apusiere ale deeystee © aie ete aie Se Lit IEA NO TAT rn) as, 0) 016) o's, nile, s\e}/oia' ei eedetors Bisteteravarslekere ais 4 c aa acie sie 's omni ltcs EURO EURIAIP TTS cle fo\fello] oat ctellsiia ays) ets wb ohayayeter onsleneteltors Salad aes ei sitoyseatnnes Soke Srarerctage 115 PAVTHOGRAPTUS) «\0jcis «ie /s\e\e/s) « aVn vais ralohotainiolalelcfeieiavcisieiavets, cetstelone MeeesHaoas Ll DENDR.O GRABINUA ttc mysimicraieielerclesielcrielele Arete lens ole leneta aie tiaras catatralstorens SionekS - 126 CATTOGRAP TUS). cic.0 sciceicie ste wets e ateastehacels ois tofe siete tele vciavers ots SU Sisieiewiate eels DT OMMONE MWA <psie!s:c10oredeteseiei ina stess.sieie sieeve : my lisriva:tureteretarete e eieiate ec efalarotammlents DIG OGRAP TUBS. ie citisleeisafoieiere = o's sveresejasvaustos SAR Ashen stearelbusls ae cee St KIMPAMNOGRIAE TUSiertater-.clevele ere es ule teretarevetnie etarclalate ciate: ateraycharcvaloh otevereneroraiteitelaletenmel 0

SUPPLEMENT.

Descriptions of Graptolites from the Utica slate, introduced for comparison and illus-

tration, 143-147.

RINTDTI Ne tisic is Osrows love iaceteiniovel ofatevaleleve/ave laleneliaga tenes rates ateletempetereieiuietale ala\tesajetufarmials (ere etalereteterets

149

APPIMAVINEISS “(ola cs a's roreieh casera vejulotalaye tare fevereltiloleveleilein iaieha‘oteve feratavelaie,slavarereieicis cteiterelere reve sranaratn ts tate mL Ene

ERRATA.

Page 146, 6th line from bottom, and page 147, 4th line from bottom, for Rurxo- GRAPTUS read RETIOGRAPTUS.

Page 147, second line from bottom, read “ The frond four times enlarged.”

GRAPTOLITES OF THE QUEBEC GROUP.

CHAPTER I.

INTRODUCTION. § I.—NATURE AND FORM OF GRAPTOLITES.

Until recently the graptolites were, with two or three exceptions, known only as simple, straight, or slightly curving linear stipes or stems, usually lying in the same plane upon the slaty lammee in which they were imbedded. Nearly all these were evidently fragmentary, and, though varying some- what in their proportions, rarely exhibited anything that could be regarded as the commencement or termination of their growth or development. These bodies, in their flattened condition, present a range of serratures either on one or on both sides of the stipe; and seldom preserve more of their substance than a carbonaceous or corneous film or test of extreme tenuity. Under more favorable circumstances, these serratures are dis- covered to indicate the apertures of cellules, symmetrically arranged in reference to each other, and to the axis of the linear stipe. Others show parallel entire margins, with transverse indentations across the central portion of the stipe. This appearance we now know to be due to the direction of the pressure upon the body exerted at right angles to the cellules, and which will be explained in the sequel.

The earliest opinion regarding these fossils was that they were of vege- table origin; and they have been thus considered by some authors even at a very late period. Subsequently, they were referred by Wahlenberg, and after him by Schlotheim, to the Cephalopoda, being regarded as extremely slender orthoceratites.. This opinion may have received sup- port from specimens in such condition as G. sealaris, where the indentations are limited on each side by a continuous margin; but in such as present a single or double series of marginal serratures, the analogy seems very remote. Professors Geinitz and Quenstedt advocated the same view at a much later date; though it has since been abandoned by these authors, from more extended investigations. |

A

6 CANADIAN FOSSILS.

Professor Nilsson first suggested that graptolites were Polypiaria, belong- ing to the family Ceratophyta. Dr. Beck of Copenhagen regarded them as belonging to the group Pennatulide, of which the Linnean Virgularia is the most nearly allied existing form. Sir Roderick Murchison has adopted this view of the relations of the graptolites, in his Silurian System.* General Portlock has fully recognized the graptolites as zoophytes, and has pointed out their analogy with Sertularia and Plumularia.

The relations of graptolites with the Cephalopoda had already been fully disproved by M. Barrande (in the first chapter of his “ Graptolites de Bohéme’’), before the abundant materials for the refutation were dis- covered in the graptolites of the Quebec group ; and most naturalists were already agreed in referring these bodies to the class of Polypi, to which they doubtless belong.

More recently, Mr. McCrady, of South Osea has published a paper on the ‘ Zoological Affinities of Graptolites,”’} in which he has endeavored to show the similarity of the graptolitic forms with the Echinoderm larva, as illustrated by Miiller. There is certainly much resemblance between the enlarged figures of that author, and some forms of graptolites in the shales of the Hudson River valley; while some of the figures with central discs have a more remote analogy with certain forms from the Quebec group. Some of the toothed rods of the Echinoderm larvee likewise bear a resemblance to the graptolites figured by Mr. Suess ;$ and there are still farther analogies pointed out by Mr. McCrady, which, however, may not be regarded as of equal value by the greater number of naturalists.

For my own part, although admitting the similarity of form and of some of the characteristics which were very kindly pointed out to me by Mr. McCrady, long before his publication, I cannot recognize the analogy sought to be demonstrated. The establishment of the fact that these toothlets or serratures are the extensions of true cellules, each one having an independent aperture, and communicating with a common canal, should offer convincing argument against these bodies being other than polyp- bearing skeletons. But, in following the extensive series of forms now presented to us, we have much evidence to show that some of these were attached to the bed of the ocean, or to other bodies; while the greater proportion of the species and genera appear to have never been attached to the sea-bottom.

It may not be easy to determine precisely the family to which these

* Silurian System, page 694; and letter of Dr. Beck, pp. 695-6.

+ “Remarks on the Zoological Affinities of the Graptolites, by John McCrady, made before the Eliot Society of Natural History of Charleston, S. C., at the meeting of July 15, 1857.” [Extract from the Proceedings, vol. i.]

t Naturwissenschaftliche Abhandlungen. Vierter Band. Tab. viii and ix.

GRAPTOLITES. i

graptolitic forms should be referred ; nor is it certain that the extensive series now presented can all properly be referred to a single family. General Portlock has suggested that these bodies may constitute ‘“ several genera belonging even to more than one order.”’* That they are true Polypi, I believe we shall be able to show, both from analogies already established by various authors, and also from their mode of development or reproduction as exhibited in some of the species.

The specimens which have usually been observed or represented are simple disconnected stipes, doubtless the dismembered or fragmentary portions of fronds, which, presenting in the different species great varieties of form and aspect when entire, are nevertheless composed of parts so similar that these fragments, though indicating specific differences, offer little clue to a knowledge of the entire form.

The name Graptolithus was established by Linnezeus in the first edition of his ** Systema Nature,” 1736, and applied by him to the straight or curved forms which are serrated (celluliferous) upon one side only, of which G. sagittarius has been regarded as the type.t The propriety of this term is more readily perceived in its application to the fragments of the stipes of monoprionidian forms than to the central portions of the body of the same. In the spirally-enrolled forms, or those with four or more stipes uniting in a central disc, as well as in the variously-branching forms, the analogy is not so perceptible.

Taking those species which, in the form of their cellules and in the separated fragments of the frond, would be referred to Graptolites proper, and tracing them, as we are now able to do in many species, to their perfect condition, we find a great variety of form and mode of growth. In the simplest of these we have two stipes diverging from a radicle, or initial point; and the parts remain so complete as to admit of no doubt

Fig. 1.

ECO DDL»

GRAPTOLITHUS PENNATULUS.

that this is the entire skeleton of the animal. ‘The cellules near the base of the stipe are not so fully developed ; while also those near the extremi- ties have not reached their full dimensions, and the last one is sometimes barely perceptible, or just assuming its form from the common body. These characteristics are perceptible in the figures upon plates i, 11, and i.

In the next stage we have four simple stipes diverging from an initial point, and all evidently entire, as shown in the development of the cellules.

* Geological Report on Londonderry, &c., p. 318. } I shall elsewhere endeavor to show that G. scalaris is a diprionidian form exhibit- ing only one margin.

8 CANADIAN FOSSILS.

Fig. 2.

GRAPTOLITHUS BRYONOIDES.

In some species of this mode of growth, the bases of the stipes are united in a more or less expanded dise or cup of the same substance as the body of the graptolite. The form of this dise is shown on plates v, vi, Vii, vill, and ix, and also in the accompanying figure of Graptolithus Headi.

Fig, 4. Fig. 3.

GRAPTOLITHUS. OCTOBRACHIATUS,

In a farther development in the same direction, we have fronds with eight simple stipes, which may or may not be united in a central disc, as in the accompanying figure.

‘GRAPTOLITES. 9g

In Graptolithus Loganit we have numerous simple ‘stipes united in a central disc or cup; while in some specimens otherwise precisely similar, we have no remains of the disc. © In all these species the parts are disposed in a symmetrical and bilateral arrangement.

Figs. 5 and 6.

-GRraPtoLitaus Locant.

The stipes of this species do not bifurcate beyond the disc, and there

10 CANADIAN FOSSILS.

are no cellules below the last bifurcation. The number of stipes in different individuals varies from sixteen to twenty-five, so that this charactercannot be made of specific importance. In another similar species without a central disc, from the Hudson River formation, we have above forty stipes, which do not bifurcate, so far as known, beyond the commencement of the cellules.

Fig. 7.

GRAPTOLITHUS MULTIFASCIATUS.

The separated and broken stipes referred by me to Graptolithus sagit- tarius* are probably of this species, occurring as they do in great numbers in the same beds in which this was found.

In other species with a similar general arrangement of parts, the main stipes are frequently bifurcated ; the bifurcations beginning near the base, and continuing as far as the parts can be traced in the stone (fig. 8). In some of the species of this character the cellules begin near the base of the stipes, while in one species they are not known to exist except on the outer branchlets.

Thus far we trace these forms through what appear to be very natural stages in the progress of development of the parts, which are all constructed upon the same plan, presenting only natural, and we may almost say con- sequent modifications.

The character of stipes and cellules in all these is such that the sepa- rated fragments would afford no means of indicating whether the part belonged to a two, four, or eight-stiped species, or to those with numerous simple stipes, or with branching stipes, unless the fragment retained a bifurcation.

A variety of form is exhibited in the division termed Dendrograptus, in which we may conceive of the numerous stipes near the base becoming

* Paleontology of New York, vol. i, page 272, pl. 74, fig. 1.

GRAPTOLITES. 11

Fig. 8.

GRAPTOLITHUS FLEXILIS:

with a portion enlarged.

conjoined into one strong stem, with the bifurcating branchlets spreading above, and this stem probably fixed in the soil. We then have a represen- tation of the typical forms of this genus, as in the accompanying figure, and as illustrated on plate xvii, figs. 8 and 9, of this memoir.

Fig. 9.

DENDROGRAPTUS HALLIANUS.

In this species, as shown in the enlargements of the branchlets, we have

12 CANADIAN FOSSILS.

a form of cellule similar to that in observed fragments of the ordinary species of graptolites. The cellules are very minute, and, from the frequent ramifications, this would probably always be recognized as a branching species.

Some of the forms of Dendrograptus have slender spreading branches, and less rigid stems than the typical species, but still retain the angular cellules, as in figs. 1 and 2 of plate xvii. From these we pass almost imperceptibly to the slender spreading forms which I have termed Callo- graptus, plate xix, in which there is, apparently, some slight modification in the form of the cellule ; and on the other hand, there is an almost insen- sible gradation to the Dictyonema, plate xx, in which the branches are connected by lateral bars, and the whole developed in a flabelliform or funnel-shaped. frond, with angular cellules on the inner margins of the branches. (Fig, 10, plate A.)

DICTYONEMA RETIFORMIS.

There are certain forms of graptolites, which, though possessing linear straight or slightly curving stipes and angular cellules, like the typical species, have yet a different aspect, and do not so naturally fall into the series. Among these we find Graptolithus divergens (fig. 11), where the bilateral relation of the parts is still shown, but the celluliferous stipes or branches are arranged on the two sides of a slender stipe or rachis, and diverge on each side from what appears to be the centre or initial point.

Different specimens show some slight variations of these characters, but not any essential differences.

GRAPTOLITES. 13

GRAPTOLITHUS DIVERGENS.

Another form, which we know only in small individuals, is illustrated in the following figures, which remind one of some forms of the recent genus Crista.

Fig. 12. Fig. 13. Fig. 14. Fig. 15.

(These figures are enlarged to twice their natural size.)

Tn another form with similar angular cellules, we have the following illus- trations of the mode of occurrence of the species.

Fig. 16,

GRAPTOLITHUS GRACILIS.

14 CANADIAN FOSSILS.

Fig. 17. Fig. 18.

$e we

GRAPTOLITHUS GRACILIS.*

We have still another group, presenting some differences, more particu- larly in the development and form of cellules, than in their general form ; and seeming in some species to unite the characters of those having a single range, with those having a double range of cellules. The simpler forms of this type are similar to the two-stiped forms of the first series ; but in all those, whether of two, four, or more stipes, the cellules are developed on the upper side, or that side opposite to the initial point. In species like G. sextans, G. divaricatus, and others of this type, the cellules are on the lower, or same side with the radicle.

Fig. 19.

GRAPTOLITHUS DIVARICATUS:

and enlargement of cellules.

In the accompanying figure of G. divaricatus, the frond consists of two simple uniserrate stipes ; and the same is true of Gf. sextans, except that

* The fig. 18 was theoretically constructed, but has since been verified by the discovery of a specimen having the same form and arrangement of parts.

GRAPTOLITES. 15

it is united at the base for the length of a single cellule. In G. furcatus the stipes are conjoined for a distance of two or three cellules above the base.

In G. ramosus, a8 shown in the following figure, the lower part of the stipe, for a considerable distance, has a range of cellules on each side, parallel with the axis ; and becoming bifurcate above, it presents two stipes or branches, each with a single range of cellules. All the species of this group have a peculiarity in the form of the cellules, which will be noticed hereafter.

Fig. 20.

Y

GRAPTOLITHUS RAMOSUS.

These species, in their mode of growth alone, present forms which might be regarded as intermediate between the mowoprionidian and diprionidian groups; though the typical forms, G. pristis and allied species, never show any tendency to a division of the parts of the stipe ; and we shall observe, as we progress, that these forms are connected with other differences of structure.

Fig. 21.

GRAPTOLITHUS PRISTIS.

The species of this type (Diprion or Diplograptus) are simple linear or

é

16 ; CANADIAN FOSSILS.

sub-linear stipes, bearmg a range of cellules on each side, often showing an initial pomt orradicle at the base, and an extension of the slender axis above and beyond the celluliferous portion.

From these forms witha double series of cellules, we pass to the broad foluform stipes, which are apparently composed of four semi-elliptical parts conjoimed along their straight sides, and thus present four ranges of cellules. These forms (Phyllograptus) are, in some species, broad and short, while others are elongate, with sub-parallel sides, as shown in the accompanying figures.

[See also plates xv and xvi. ]

Fig. 22.

PHYLLOGRAPTUS AUGUSTIFOLIUS. PHYLLOGRAPTUS TYPUS.:

(See illustrations under generic descrip- a group of separated stipes as they lie upon tion, and plates xv and xvi.) the surface of the shale.

From the occurrence of a large number of these leaf-like stipes, some- times crowded together in a small space, I have inferred that they may have grown as Retiograptus. (Plate xiv, fig. 9.)

Following the forms with a double series of cellules, are those of similar general form, the Retiolites, which are known only as simple stipes. (Plate xiv, figs. 1-5.)

In the Retiograptus we have simple elongate stipes; and in one form (plate xiv, fig. 9) we have the stipes united by slender basal extensions in a spreading frond, in a manner not unlike some of the graptolites proper, with the parts in bilateral arrangement.

In the genus Rastrites of Barrande we find a departure from all of the preceding forms in the slender stipes with delicate ‘slender tubular

GRAPTOLITES. . 17

cellules.* The species of this genus, so far as known, have the cellules developed on one side only of the:stipes or branches ; though there seems no reason why we should not have species with cellules upon the two sides of the axis.

The species for which I have proposed the name Zhamnograptus con- sist of slender cylindrical stipes and branches, some of them very similar in general aspect to Rastrites, but the alternating branches are long and slender, and we have found no appearance of cellules on any part of the specimens known.

Tn the accompanying illustration the branchlets are given off alternately on the opposite sides of a stipe or rachis, and the slender solid axis can be traced from the main stipe into and along the centre of the branchlets. The analogy between these forms and the celluliferous graptolites of the preceding illustrations does not appear to be very intimate, but they occur in the same beds, and the fossil has the same texture and substance.

Fig. 24.

THAMNOGRAPTUS TYPUS.

In the genus Ptilograptus (plate xxi) we have a somewhat analogous mode of growth, but there is always an aspect or expression of the fossil which distinguishes it from Zhamnograptus. In one species of Pizlo- graptus moreover, cell-apertures have been detected on one side of the branches or pinnulee.

In the Buthograptus we have a form bearing some analogies with the

* See illustration of Rastrites Barrandi under section iii, p. 26, of this introduction,

18 CANADIAN FOSSILS.

preceding, but the rachis is flexible, and is not known to be branched, while the slender alternating pinnule are flat and simple, as they have been observed in numerous individuals. ‘The specimen represented is even less curved than the usual condition of this species in the slaty Trenton limestone of Wisconsin.

a

Fig. 25.

BUTHOGRAPTUS LAXUS:

enlarged.

Still more obscure, and perhaps remote in its analogies with graptolites, is the genus Jnocaulis, consisting of flattened scabrous stems, associated with Dictyonema in the shale of the Niagara formation, which, from their carbonaceous substance and apparent graptolitic texture, I have referred

to the Graptolitide.

Fig. 26. °

INOCAULIS PLUMULOSA.

GRAPTOLITES. 19

§ I].—THE CENTRAL OR BASAL PORTIONS OF THE GRAPTOLITE.

1. The radicle, or initial point. 2. The funicle, or non-celluliferous connecting portions of the stipe. 3. The central disc.

~ 1. The Radicle, or Initial Point.—In the most simple forms, or those with two stipes, as shown in all the figures on plate 1, there is a slender initial process, which I have termed the radicle. This presents a greater or less development in the different species ; in some being reduced to a mere pustule, or scarcely perteptible point, while in others it attains a quarter of an inch or more in length. Although in none of the species with a single range of cellules does this part show absolute evidence of having been attached to any other substance at the maturity of the fronds, yet it is possible that in the earlier period of its growth, the body may have been temporarily attached at this point to the sea-bottom or to some object ; though all the evidence is opposed to this view.

In some of the bi-celluliferous forms, and probably in all of them, there is a somewhat similar extension below the base of the celluliferous portion of the stipe, though it is usually more slender; but whether this is always the true initial pomt of the whole body, or whether it is only the broken point of attachment to a frond, may sometimes admit of doubt. It is con- spicuous in Phyllograptus typus; and we observe this feature also in Retiograptus ; but in one species of this we learn that it is only a broken process of attachment of the individual stipe, which existed as one of the members of the entire frond, the true initial point of which would be in the centre of the whole. (Pl. xiv, fig. 9.)

In all the forms of Graptolitidee which appear to have been free, the initial pomt or radicle is in fact the commencement of the solid avis, which will be noticed farther on. In those graptolites with two simple stipes, the little radicle-like process enlarges above, and the stipes, diverging in opposite directions, are closely united at their bases, and the cellules begin almost in the axil between the two. (Plate i, figs. 1, 3, 7, 9, and 10.)

2. The Funicle—In the graptolites with four stipes, the condition appears like that of two individuals of the two-stiped forms, conjomed by a straight connecting process of greater or less extent, with the radicle point in the centre, though often obscurely marked. This connecting process is always destitute of cellules ; and this, with its divisions, I have termed the funicle. .

In those forms with eight stipes the funicle is twice divided at its two extremities; and where there is a greater number of simple stipes, it is

20 CANADIAN FOSSILS.

correspondingly subdivided. Neither the central portion, nor any of its subdivisions, becomes celluliferous ; and these parts are not termed stipes or branches, according to the views I have entertained. It is only beyond the last subdivisions of this part of the body, as in G. Logant, that the celluliferous parts, or the true stipes, commence.

In one of the proper branching forms, however, the cellules begin immediately beyond the first subdivisions of the funicle, as in the four- stiped species. (Fig. 27.)

GRapPtoLtitaus Minzsi.

These barren, or non-celluliferous portions of the graptolitie body, are not otherwise essentially different from other parts of the stipe. In the absence of cellules they are consequently more cylindrical, and apparently more solid, asif the test were thicker, and the common canal less developed than in the other parts of its extent.

3. The Central Dise.—In several of the species having four simple stipes, in one species with eight, and in another with a larger number of simple stipes proceeding from a common centre, we find their bases united by a thickened corneous expansion of the same substance as the body of the graptolite. This appears to be composed of two laminz, which, at least in the central portions, are not conjoined, and the space-is probably occupied by some softer portion of the animal body. (Plates v-ix.)

The substance of the disc sometimes extends along the margins of the stipes, producing an alation, as in G. alatus. (Pl. vi, fig. 9.)

This arrangement of the parts of the body seems obviously adapted to give strength and support to the bases of the stipes ; but: beyond this it probably serves other purposes of the animal economy. In several specimens of G. bicornis there is a disc or bulb at the base of the stipe, which, spreading between the two oblique curving processes, envelopes, in the compressed condition of the specimens, some of the celluliferous part

GRAPTOLITES. - Al

of the stipe at its base. In other specimens we have a crescent-shaped extension, as if the disc were in process of development, or perhaps of absorption. Much the larger proportion of the specimens of this species, however, are destitute of disc or bulb, and have every appearance of being complete without this appendage.

These aspects of the species are shown on plate A, figs. 18, 15, 16, and 17.

How far the bulb-like appearance at the base of some of the species of Dendrograptus may correspond to the disc of G. bicornis, I have not at this time the means of satisfactory determination.

§ III.—tTHE NATURE AND PARTS OF THE STIPE PROPER.

1. The solid axis.

2. The common canal,

3. The calycles or cellules.

4, Nature and ornaments of the test.

1. The Solid Avis.—All the graptolites proper have been found to be provided with a slender solid axis,* while this feature has not been satis- factorily proved in regard to Dictyonema, and to some other forms.

In those species having a single series of cellules, this axis is upon the back of the stipe, or on the side opposite to the celluliferous margin; and in the branching forms it follows all the ramifications. In all the speci- mens where it has been observed, it is a slender cylindrical or flattened filiform solid body. In some extremely compressed specimens, this axis appears as a slender elevated ridge along the back of the stipe; and where the substance of the body has been removed, it leaves a narrow groove along the margin of the impression.

In the examination of large numbers of specimens of the monoprionidian species, we have never found the axis prolonged beyond, or denuded of, the cellules; as shown in G. colonus, by Barrande, in his Graptolites of Bohemia. (Plate ii, fig. 5, of that memoir.)

In all the specimens where the extremities of the stipes are entire, as represented in plates i, ii, and iii of this memoir, there is never any extension of the axis beyond the last partially developed cellule; and the number of specimens in this condition is considerable.

Tn the graptolites with two series of cellules, the solid axis is very

* In those species with a single series of cellules, M. Barrande has ascertained that this axis is solid and cylindrical, its diameter not exceeding 4 millimetre, and its struc- ture apparently fibrous. (Graptolites de Bohéme, page 4.)

B

23 CANADIAN FOSSILS.

frequently seen extending beyond the celluliferous portion of the stipe at _its outer extremity ; while the radicle appears like the continuation of the same below the base. ‘The axis thus appears to be the foundation on which the other parts are erected. In those specimens, however, which present so great an extension of the solid axis beyond the stipe, the cellules may have been removed by subsequent causes.

I am able to corroborate to some extent the observations of M. Barrande in regard to the apparent double character of this axis. In some ex- tremely compressed specimens it is marked by a longitudinal groove or line of division ;* while in others, a double impression has been left by the removal of the substance.

In some specimens, particularly the younger ones, the solid axis has been seen extending beyond the base of the stipe, as a duplicate process, exhibiting a character as of a double radicle. In some solid specimens of one species, where the tube had been filled with calcareous mud, I am able to detect only a single round point; and a longitudinal section of the same species presents a slender filiform axis. It may be, however, that the parts are so minute and so closely united, as to render them undis- tinguishable.

In another species, with two rows of cellules, and in which the latter are of very different form from the preceding, the solid axis is a thin flat apparently double plate, extending across the entire transverse diameter of the tube, which is more than two-thirds as great as its longer diameter. The place of the axis is marked by a longitudinal groove on each side, not in a direct line, but slightly undulating to correspond with the cellules. M. Barrande conceives that the joining of the two plates of this axis may leave a very flat intermediate tube ; and in our specimen, there is appa- rently an extremely narrow space between the two. He farther supposes that each of these plates, composing the double axis, is separable, by decomposition, into two lamine, as illustrated in plate ii, fig. 3, of the work already cited.

The entire appearance of the species (plate A, fig. 10) is that of two monoprionidian stipes joined together at the back, the line of junction being indicated by the groove.

In one species of fetiolites there is a strong excentric or sub-exterior axis, which is nearly direct ; and in the same individual there is another undulating axis, to which the cell-divisions of one side are attached. In the Retiolites of the Quebec group, one side of the stipe shows a very distinct axis, while upon the other side it is very obscure.

In Retiograptus we have a very distinct central axis projecting below

* The aspect presented by the axis, when marked by a longitudinal groove, is pre- cisely that which a hollow cylindrical body would have if extremely compressed.

GRAPTOLITES. 23

the celluliferous portion of the stipe, and, in one species, uniting in a funicle, and forming part of a compound form. In another species, the simple stipes present similar features, showing at one extremity the duplicate character of the axis.

In Phyllograptus, the central axis is apparently composed of four slender flat lamin ; but we have had no means of examining this part of the body in a satisfactory manner.

2. The Common Canal.—lIn all graptolites with a single series of cellules, there is, between the bases of these cellules proper and the solid axis on the back of the stipe, a continuous sub-cylindrical space or canal, which has been occupied by the body of the polyp, from which the buds, with their calycles forming the cellules, take their origin, and are thrown off at regular intervals. :

All the specimens which I have examined confirm this view; and in some of the species where the extremities are apparently entire, we observe the incipient development of the young cell from the common body. In those specimens filled or partially filled with the substance of the surround- ing rock, this canal is easily distinguished ; while in compressed specimens there is always a flattened space between the bases of the cell-partitions and the solid axis.

Tn those graptolites with two ranges of cellules, we have apparently a duplication of those with the single series, the two solid axes being jomed together, leaving a common canal or body on each side at the base of each series of cellules. If however the common body were thus divided, it would be by the solid axis becoming a flattened plate. This appears to be true of some species (as for example, plate A, fig. 10), while in others there is only a simple filiform axis visible. In this case, of course, there is not an entire division in the common canal after the manner of the other species. ‘This will appear farther on, under the illustrations of the structure of these bodies.

In Retiolites, the common body occupies the central portion of the stipe, giving origin to a series of buds on each side, while it is not divided by a central axis.

In some species the common body seems likewise to have more extensive functions ; for in such forms as G. divergens and G. gracilis, there is a long slender rachis, or tubular body, destitute of cellules except at its two extremities, and apparently consisting of a solid axis and a common canal, from which originate, at regular intervals, simple small stipes with solid axis, common canal, and cellules.

This appears to be one step farther in our knowledge of the origin or mode of development ; but it shows that a stipe or main axis may produce in one part celluliferous stipes, and in its extremities develop only cellules, as we see in the continuation of the main axis of G. gracilis and

24 CANADIAN FOSSILS.

G. divergens, where the continuation of this common rachis is marked by marginal cellules of the same character as those of the lateral stipes.

The common body therefore appears to perform the double function of developing the buds which elongate into stipes with cellules, and also of simple cellules; or we may consider the celluliferous extremity of the rachis, or main axis, as the termination of the reproductive process, or as analogous to one of the lateral celluliferous stipes. In the Sertula- rians we have something analogous to this mode of development. Some of the species have cellules along the common or main trunk, and produce at intervals branches or branchlets in place of cellules; others have a common body, or main stem, entirely destitute of cellules, but producing branches on each side (opposite or alternate, as the case may be), which branches produce cellules only.

So long as this rachis gives off only celluliferous stipes, it is analogous to those parts of the simple graptolites which I have termed the funicle, having within itself the sources of this development of the several parts. The mode of development differs from that of the branching forms, inas- much as the branches proper arise from a division of a cell-bearing stipe or branch, and of course a division of the solid axis and common body.

In Retiograptus, some specimens show the cell-divisions reaching nearly to the axis, leaving room on each side for a narrow common body or canal ; while in a species from the Utica slate, which presents one side of an entire frond, the cell-divisions of the exterior side all reach to the axis, leaving the common body on the inner or upper side. In a species from Norman’s Kill, near Albany, there are three parallel ranges of reticu- lations, with apparently two filiform solid axes, forming the divisions between the three meshes. This structure probably occupies one side of the stipe, while the common body may occupy the other side.

In Phyllograptus, the cell-partitions reach very far towards the centre, and the space left for the common canal is very small. We infer from the better-preserved specimens that there is a slender common canal at the base of each range of cellules. These several canals may or may not communicate with each other.

3. The Calycles or Cellules: their form and mode of development.— Since a large proportion of the specimens of graptolites which come under our observation for the purposes of study or otherwise, are fragmentary, it becomes of much importance to know the general characters of form and mode of development of the cellules.

In the preceding section it has been shown that the cellules, or the inhabitants of these cellules, are not independent, but all have their origin in a common body, which fills the longitudinal canal, and that they remain in constant connection with the same throughout their existence.

The calycle or cellule is formed by budding from one side of the com-

GRAPTOLITES. a5

mon body, not unlike many of the Sertularians, except that the cellules are generally close together at their origin.* They are usually more or less oblique to the direction of the axis, as is clearly indicated by the cell- partitions ; and the degree of obliquity often indicates specific distinction. The cellules are for the most part contiguous at their origin, and they sometimes remain in contact throughout their entire length ; but in the greater number of species there is a small portion of each one free on one side towards the aperture. This character is shown in numerous examples. (Plates i, 11, and i.)

In some forms the cellules are contiguous in their lower portions, while the entire upper or outer part becomes free, as seen in Gt. Clintonensis (plate B, figs. 1, 2, and 3); while in one of the bi-celluliferous species _ from Iowa, the cellules are distant from each other at their origin, and the upper extremity of one scarcely reaches to the base of the next in advance (plate A, fig. 10) ; and they are therefore not properly in contact in any part of their length. The same is more emphatically true of Rastrites, (fig. 27), where there is a large interval between the bases of the cellules, which are often nearly rectangular to the axis.

Although we regard the cellule as limited by the cell-partitions, yet in well-preserved specimens there is sometimes a swelling of the test of the common body below the cellule, indicating an enlargement of the parts at the bases of the buds. In one species there is an evident undulation of the

axis, corresponding to this enlargement of the parts in the common body. (Figs. 10 and 11, plate A.)

* The mode of budding and the form and arrangement of the cellules in the Sertula- rians are shown in the accompanying figures of two species of Sertularia (figs. 1 and 2) from our own coast. Fig. 3, with a range of cellules on one side only, is a Plumularia.

Fig. 1. Fig. 3.- Fig. 2.

26 CANADIAN FOSSILS.

|

RAstTRITES BARRANDI:

Fig. 28.

natural size, with a portion enlarged. The cellules consist of long slender tubes.

In the diprionidian species, the cellules on the two sides of the stipe are alternating, so that the bases or the apertures are opposite the space between two others. This is more especially shown in the enlarged figures 10 and 12, plate A.

In much the larger proportion of species, the body of the graptolite and the cellules are so extremely compressed, that they appear only as serra- tures along the margin, with distinct impressed lines marking the cell- divisions. The exterior margin of these serratures indicates in an approx- imate degree the outline of the aperture ; and the frequently occurring mucronate extension at the extremity of the cellule is produced by the continuation of the cell-partition, or sometimes by an outgrowth from the margin of the stipe above or below the aperture.

Were the cellules isolated, their prevailing form would be that of an elliptical tube or sac, the length of which is greater than either of the two diameters. When they are in juxtaposition, however, the contiguous sides are flattened, while the lateral or external surfaces are usually more or less curved, particularly near the aperture. In a larger proportion of the species, the calycle becomes slightly expanded towards the aperture ; but in a few examples there is a distinct contraction above the middle, and the aperture is smaller than the base. Generally, however, the smaller diameter is just at the junction with the common body, or at the junction of the cell-walls with the walls of the common canal.

In asingle diprionidian species, where the specimens are not distorted by pressure, a longitudinal section of the stipe in the direction of its greatest diameter (plate A, fig. 12), shows the cellules scarcely narrowed at their origin with the common body; while in a lateral view of the specimen,

GRAPTOLITES. YH

the base of the cellule is seen to be much wider than the orifice. (Plate A, fig. 10.) :

In many of the species a transverse section of the cellule near the base is quadrangular, becoming more rounded towards the aperture; and when the upper part of the cellule is free, the aperture is round or elliptical, and in some specimens the calycle is elliptical or cylindrical throughout its entire length: We have examples of the quadrangular cellules in G. extensus (plate ii, fig. 16) and G. octobrachiatus (plate vii, figs. 5 and 7); as well as in two species of Phyllograptus (plates xv and xv). Where the cellules are more nearly isolated, they approach more and more to the cylindrical form. As examples of cellules contracted towards the aperture, we have Graptolithus priodon, Barrande, and G. Clinton- ensis, Hall. (Plate B, figs. 1, 2, and 3.)

M. Barrande has remarked that from the circumstance of the partial or complete isolation of the successive alveoles of the same series, we may easily conceive that the walls of contact in contiguous cellules should be double. This fact he has ascertained from decomposing specimens of G. priodon ; and we have the same evidence in some of our species. In the cellules of the ordinary mode of development, each one is an independant part of the organization, and is provided with its individual body and c¢ell-walls, as if each cellule were isolated. Whenever two of these are in contact, the cell-walls coalesce as far as the contact continues ; but when becoming free, the cellule assumes its normal condition. In some specimens of Phyllograptus we find this evidence of double walls in the cell-partitions.

In G. putillus, illustrated on plate A, figs. 10, 11, and 12, the cell- walls, although contiguous to and adjoming the walls of the body (and not free), do not coalesce, but are readily separable without fracturing their substance.

There are cellules however where the production of the calycle by budding from the common body is not so obvious. These forms are like G. bicornis and G. antennarius, where the orifice is a simple trans- versely-oval aperture in the side of the stipe. In the flattened speci- men it appears like a rectangular or slightly oblique, semi-oval notch in the margin. Its true form is perceived only when the cavities of the polyp have been filled with mineral matter, or when the stipes are flattened ver- tically agamst the apertures: they then give the form which has been described as G. scalaris. This form of cellules is shown on plate A, figs. 1 and 2, which are enlarged from a specimen retaining nearly its original proportions. Just within the limits of the cellules, and extending the entire length of the stipe, there is a longitudinal depressed line; and along this line, and running thence almost rectangularly to the outer limits of the stipe just above the aperture, the cell-partitions join the exterior test, and

project in an extended border or flange.

28 CANADIAN FOSSILS.

In specimens stripped of the test, where the interior has been filled with stony matter, the cell-partitions present the appearance shown in fig. 3, plate A; while there is a large central space apparently occupied by the common body, but without the appearance of a central axis on the exterior surface. When the surface is ground down to a plane intermediate between the exterior and the centre, it presents the aspect of fig. 4 ; and when the cutting is carried to the centre, it gives the characters of fig. 5, the cell- divisions apparently reaching to the axis.

The general form of this stipe in section (fig. 6) approaches that of Retiolites, as shown by Barrande and Geinitz; and in the arrangement of the common body and axis there is a departure from the typical diprioni- dian forms of Graptolithus. In this transverse section we have a some- what concavo-convex form, which is narrower on the concave side. There is a central or sub-central point indicating the filiform solid axis; and on each side of this are the divisional cell-walls, which produce a shght con- traction of the exterior walls of the stipe at the inner limit of their attach- ment. Another section, fig. 7, shows the same features, together with the remains of two other cell-divisions, neither of which reach to the exterior walls of the graptolite; and the one on the right hand shows the narrow extremity just before joining the axis.

These sections, together with numerous other longitudinal, transverse and oblique sections, compel us to conclude that this graptolite possesses a filiform central or sub-central apparently solid axis ; and that the cell- partitions originate from, or are joined to this axis. ‘These cell-partitions appear to consist of triangular plates, which have an unequally arching or convex upper surface, and a concave lower surface. ‘This form of cell- partitions would Jeave the alveoles to communicate at their bases with the common body on each side.*

In some forms having cellules of this character, as in G. bicornis proper, there is, in the flattened stipes, an external ridge, as if indicating the june- tion of the axis with the external walls. But in examples where this axis extends beyond the celluliferous portion of the stipe, it is compressed, having the aspect of a flattened cylindrical filiform body. It has no appearance of haying been flat, or laterally extended within the body of the stipe.

In the ordinary forms of graptolites the orifice of communication between the cellules and the common body is eal round, oval, or quadrangular ;

* The cell-partitions in this form of graptolites are represented as they appear to exist in the solid specimens examined, on plate A, fig. 9; where, curving gently downwards on their exterior margins from the upper edge of the orifice, they turn more abruptly towards the axis, while the central portion extends obliquely to the axis, leaving a broad arch above, which gradually becomes angular as it approaches the axis.

GRAPTOLITES. 29

and this appears to be true of all the species with a single range of cellules, and also of the ordinary forms of those with two ranges of cellules, where the common body. is divided by a longitudinal axis.

In Rettolites, where there is no well-marked division limiting the com- mon body, the union of the cellules with it is not so well defined; nor does there appear to be in these forms a continuous cell-partition: the cellules open in a quadrangular aperture, which is a little oblique to the transverse diameter.

In those graptolites with the simple transversely-oval orifices in the test, as G. bicornis, the arrangement of the common body and the communica- tion of the cellules differ from all the other forms. ‘There is an apparent double communication with the common body, giving not only the usual bilateral arrangement of the parts generally, but a bilateral arrangement of the parts in the individual alveoles.

The external orifice of the cellule in graptolites is extremely variable in form, and in its relative direction to the body of the cellule, and to that of the general axis. In a large proportion of the species, the aperture is oblique to the axis of the cellule, a little expanded, and thickened at the margin. The lower or posterior edge is often prolonged into a mucronate point or expansion. ‘This feature, combined with the various degrees of curvature at or near the aperture, produces a great diversity of external expression in the orifice.

In G. nitidus, plate i, and in G. similis and G'. extensus, plate ii, the plane of the orifice is nearly rectangular to the axis of the cellule; while in G. bifidus, G. pennatulus, and others, the margin is produced into a strong mucronate extension. In G. octobrachiatus the line of the cell- margin makes an angle of more than 90° with the axis of the cellule.

In mature individuals of G. Clintonensis the upper part of the cellule is re-curved, and the orifice opens downward nearly at right angles to the general axis, having a slight spreading and thickening of the border. In less mature individuals the orifice is apparently angular, and opens upward, while the plane of the aperture makes less than a right angle with the direction of the general axis. It would appear that in the progress of growth the cell-walls are continued, gradually contracting above, and, after becoming free from the adjacent cellule, form a slender, gradually cury- ing tube, which in mature individuals has its orifice directed backward.

In Dendrograptus, the form of the orifice and outline of the aperture present variations similar to those of the simple uniserrate graptolites ; but some species show modifications in the form of the cellule which do not accord with the more simple forms. In Dictyonema, the cellules are not fully known ; the orifices are marked by a prominent mucronate extension, and apparently simulate the more common forms of graptolites. (Fig. 5, plate B.)

30 CANADIAN FOSSILS.

In the bi-celluliferous species the compressed specimens present the plane of the orifice, sometimes rectangular to the general axis, sometimes with the outer margin a little advanced, makmg an acute angle with the axis of the cellule, while sometimes the plane of the margin of the aperture is rectangular to the axis of the cellule, or rarely makes with it an obtuse angle. ‘The cellules of Retiograptus, which have not yet afforded means of satisfactory examination, apparently have their orifices nearly rectan- gular to the general axis of the stipe.

In one of the forms of the bi-celluliferous graptohtes the cellules are sub-elliptical tubes, with an orifice of corresponding form, without extension beyond a slight thickening or callosity at the margin of the orifice. The plane of the cell-aperture in this one makes an obtuse angle with the direction of the general axis.

In forms like . dicornis the external orifice is transversely oval, with or without a projection and thickening of the test from the cell-partition above the orifice, or extension of the test.

4. Ornaments of the Test.—The compressed condition in which the graptolites usually occur is unfavorable to the preservation of any minute surface-markings, or ornaments of the test.

In many of the species, fine striz, parallel to the margins of the cell- apertures, are perceptible, and in the larger number of species this mark- ing is all that is preserved. There is sometimes a granular appearance of the surface, but I have not been able to satisfy myself that this is the actual surface-texture ; it may be a condition induced by mineralization. In a few examples there is a row of minute pustules at the base of, and corresponding to the cellules.

The stems and branches of Dendrograptus, Callograptus, and Dietyo- nema are irregularly striated. In typical species of Retzolites the test is finely reticulate ; while in the species from the Quebec group, this texture, if existing, is so fine as not to be readily resolved by an ordinary lens. The surface however has not the appearance of entire smoothness, as in most of the ordinary graptolites.

The chief ornaments of these bodies are the mucronate extensions of the test, usually from the lower margins of the cellules, but sometimes from the upper margins. In ordinary forms of the species, with single, and with double ranges of cellules, the mucronate or setiform extensions are usually from the lower extremity of the cell-aperture, as illustrated in fig. 29.

In all those forms of which G. bicornis may be regarded as the type, these processes, when existing, are extensions of the test above the aper- ture, so far as observed (pl. A, figs. 1, 8, 9); or as in species of the character of fig. 20, plate A.

In some species, as G. quadrimucronatus (plate xii), there is a

GRAPTOLITES. » a

Fig. 29.

ppt pa tt tbl TALE od oer

GRaApPToLitHus WHITFIELDI:

twice enlarged.

mucronate pomt extending from each angle of the cellule ; as also in G. testis of Barrande ; except that in the eBecuae species these appen- dages are more rigid.

In Phyllograptus typus and P. ilicifolius, these processes are apparently the extension of the angles of the cell-partition.

The cellules of Dendrograptus, Callograptus, and Dictyonema some- times show mucronate extensions from their outer margins. In Retiolites the cellules sometimes terminate in a plain margin, and in one species the divisions are extended in short strong mucronate points. (Plate B, figs. 5 and 21, and plate xvii, fig. 6.)

All the species of Retiograptus have the margins of the stipes gar- nished with slender mucronate points, corresponding to the cellules, and extending almost rectangularly to the axis. (Plate xiv, figs. 6-9.)

These ornaments are not always uniformly developed in the same species, or even in the same individual. In the larger proportion of specimens of G. ramosus, the margins of the cellules are apparently plain; but in the cellules of the simple part of the stipe we sometimes find a rigid mucronate point, prolonged from the upper margin or limit of the cell-aperture. (Plate A, fig. 20.) In G. seztans, the mucronate point is half-way between the two cell-apertures.

In specimens of G. sextans, and in some allied forms from the Hudson

3) ile CANADIAN FOSSILS.

——s

River formation at Marsouin, Canada, the stipes and cellules are less - fully developed than in those of the same species from Norman’s Kill near Albany, while the mucronate extensions from the cell-apertures are more conspicuous.

Besides these ornaments, there is on each side of the radicle or initial point at the base of most of the diprionidian species of graptolites, a small process, varying in length, and usually directed downwards. These processes are usually short, but often considerably extended; in some spe- cies they are very slender, while in others they are strong and rigid. In G. pristis they are frequently seen as short slender processes; while in G. bicornis they are rigid, strong, and slightly curving. In G. anten- narius, a congener of the latter, they are long and slender setiform appendages. In one species of Retiograptus they are slender setiform processes, directed downwards.

In no species of Phyllograptus have such appendages been observed ; nor have they been seen at the bases of the stipes of etiolites.

§ IV.—MODE OF REPRODUCTION AND DEVELOPMENT IN THE GRAPTOLITIDA.

As already remarked, the graptolites proper are now generally referred by authors to the Radiata; while some forms which I include in the family have been heretofore regarded as reticulate bryozoans, or as gor- gonians. ‘The nearest analogues in the recent fauna appear to be among the group Pennatulide, or in the Sertularide ; but in all these there is no absolute identity in the mode of development or character of cellules, so far as my observation has extended.

In nearly all the true bryozoan forms among fossils, we have the means of tracing the relations and analogies, both in manner of growth and reproduction, throughout all the successive geological periods, and in the present fauna. It becomes therefore more difficult to discover such analogies for the Graptolitide, since the graptolites proper disappear from existence in the Silurian period; and the latest form of Graptolitidee (Dictyonema) is not found, so far as now known to me, in American strata, at a later period than the Hamilton formation or Middle Devonian. From this cause, the mode of growth and development are not so readily understood as in those families which can be traced throughout the geo- logical series, and still find their analogues in the present seas.

In 1858, I laid before the American Association for the Advancement of Science a notice, with some illustrations of graptolite stipes, bearing what I then regarded, and do still regard, as the reproductive cells or ovarian vesicles. These cells first appear as small ovate buds upon the

GRAPTOLITES. 3s

margins, projecting but little beyond the regular cellules, and, becoming enlarged, form elongated sacs with swollen extremities, which are finally dehiscent; and then, as I suppose, discharging the ovules or germs, are gradually absorbed or dissipated.

Although these sacs are distinctly defined, they have scarcely any apparent substance, except along the lateral margins, which are limited by a filiform extension resembling the solid axis of a graptolite. There are likewise numerous fibres of this kind traversing the sacs; and these sometimes remain attached to the original stipe after the other parts are separated. In one example, we have conclusive evidence that they are connected with the solid axis of the parent stipe. The gradations of development in these sacs may be studied in the figures 6-9, plate B.

In the specimen fig.10 of the same plate the ordinary cellules are removed, and the fibres are still seen jomed to the axis, showing the origin of the reproductive sacs. In most specimens bearing these sacs, the cellules of the stipe are so obscure that the species cannot be determined ; but in fig. 9 we find them attached to a well-marked stipe of G. Whitfieldi.

This mode of reproduction in the graptolites shows much analogy with the Hydroidea, and would indicate the sertularians as their nearest analogues.*

Upon the surfaces of the slate where these bodies occur, there are numerous graptolitic germs, or young graptolites of extremely minute proportions, ranging from those where the first indications of their form can be discovered, through successive stages of development till they have assumed the determinate characters of the species.

In several examples, these minute germs have been detected near to and in contact with the reproductive sac ; and in one case, there is but a hair’s-breadth between one of the fibres of the sac and one of the oblique processes at the base of the germ. It cannot be said that we have detected the germ actually within the sac; but the numerous young individuals lying near them, and upon the surfaces of the same laminz, offer very good arguments for supposing that they have been thus derived.

The earliest defined form which we observe in the’ young graptolites

*In the recent Sertularia and Campanularia we find ovarian vesicles, in which a number of ovules may be enclosed in acommon envelope. These vesicles are developed along the side of a stipe or branch, and the ovules are often arranged along a central axis, each one communicating with the common axis of the zoophyte. [Jas. J. Lister, Philosophical Transactions, 1834, pp. 365-388, pl. ix. Cited also by Dana, “ Structure und Classification of Zoophytes.”]

Prof. McCoy kas stated (British Paleozoic Fossils, p. 4) that he has found near the base of the cellules of graptolites, a transverse partition or diaphragm, similar to what may be observed in some sertularians, and which he regards as proving similar rela- tions; but I have not discovered in any American specimens evidence of such cell- diaphragms.

34. CANADIAN FOSSILS.

consists of the initial point or radicle; a diverging process of similar character on each side, but not quite opposite; a longitudinal axis of greater or less extent; and a sac-like covering, or thin pellicle of grapto- litic test, which has scarcely assumed the form of cellules, but which is most extended in the direction of the common body along the solid axis. This little sac contains the germ of the zoophyte, which, extending itself as the common body in its canal along the axis, gives origin to the budding which develops the successive cellules and the gradual building up of the stipe.

The earliest condition of development is illustrated in fig. 12 of plate B.* Ata farther stage of development we have the form better defined, as in fig. 13, where the germ has assumed the general aspect of G. pristis, the slender lateral processes being rectangular to the axis.

On the left hand of fig. 8, and at the third reproductive sac below the ~ top, there are two germs visible, close to the sac, where the connection between one of these and the fibre is nearly complete. The same is shown in the enlarged fig. 11.

In figure 14 we have the germ of another form, which is unequally developed on the two sides. Figure 15 (represented of the natural size) appears to be of the same species, having reached a more definite form. Figure 16 is an oval disc, of which several more or less defined specimens have been found among the young graptolites, but I have not been able to trace it to any known mature form.

The specimens figs. 17 and 18 appear to be the young of G. dicornis, or of a similar form. In one the body is narrow, without marks of cellules, and the solid axis is not extended above the common body, being prob- ably broken off. In the other there is a greater expansion of the common body, but no cellules are visible, and the central portion of the substance is more dense, while towards the margin it is extremely thin; the solid axis is extended beyond the stipe, and the lateral oblique pro- cesses are quite perfect. This germ, with its axis and common body, had not begun to develop the cell-apertures on its margins, which may be seen at a later period.

In nearly all the young graptolites there is an extension of the common body along the axis above the incipient cellules. This is observed in the figures referred to and in the young of G. ramosus, shown six times enlarged on plate A, fig. 21.

Although I have found none of the monoprionidian forms with repro- ductive sacs attached, I have nevertheless observed what appear to be the young of some of these species, having an aspect similar to the others,

_

* All the specimens of germs or young graptolites are six times enlarged, except figs. 11 and 17.

GRAPTOLITES. 35

except in carrying the development upon one side only of the solid axis. An illustration of one of these forms is given in fig. 19, plate B, showing the base irregularly divided. These forms cannot be referred to any known mature species.

This mode of development, illustrated in numerous specimens, can be readily understood in the simple stipes whether of the monoprionidian or diprionidian character. Admitting that the examples given furnish ‘evidence of the mode of reproduction of the diprionidian forms, or those of the sub-genus Diplograptus, where we have a range of cellules on each side of a solid axis, it is easy to perceive how the germ of an analogous form may develop from its initial point two series of cellules upon a stipe, where the parts diverge im opposite directions from the common origin or initial pot. One step farther in this direction will give us the four-stiped forms, where the germ of the common body, with its additional elements of subdivision, produces the quadripartite frond; and so onwards, until we have the numerously-branched fronds and the branching stipes.

Tn all these, the germ in its incipient development will differ very little. It may consist of the radicle or initial point, with the solid axis, and the common body, separated into two, four, eight, or an indefinite number of divisions, each one bearing its solid axis and common canal. These sub- divisions sometimes all take place near the origin, which is always central ; and the divisions continue simple throughout, or do not bifurcate after they commence to develop cellules.

In others the stipes are again divided, and this subdivision is only limited by the extent of the frond. In all these fronds the parts are always arranged symmetrically or bilaterally on the two sides of the initial point ; as has been illustrated in the preceding pages.

Throughout all the monoprionidian forms, or those illustrated on the first twelve plates of this memoir, we have only modifications of the simplest form of development shown in the species of plates i and ii. Where the divisions at the base become more numerous, (and indeed in the four- stiped species, ) we find a thick corneous test, of the same substance as the other parts of the graptolite, uniting the bases of the stipes and continuing along their margins. This plate has a greater or less development, not always corresponding to the size or extent of the stipes. It is sometimes absent, apparently from accident, and some of the four-stiped species are not known to possess it; while it has never been observed in any of the species where the stipes are properly branched, or divided in the celluli- ferous parts of their length.

The interior of this corneous disc, previously described as apparently composed of two plates of the test, has probably been occupied by some softer substance, which may have been an extension of the common body, or have had in some degree the character of the common body of the stipe.

386 CANADIAN FOSSILS.

The development of the diprionidian forms, as deduced from the young graptolites which we find associated with the reproductive cell-bearing stipes, would show that these forms of graptolites exist as single and simple independent stipes from the commencement of their growth. Nevertheless I conceive that both Retiolites and Retiograptus may have existed in compound fronds, having their origin from a central point not unlike in the commencement to Graptolithus Logani, but without the central disc. These fronds were probably concavo-convex, as were the individual stipes. The solid axis, instead of being central, is placed exter- nally along the centre of the convex or outer side ; and the cell-divisions on that side reach to and join it; while on the upper or concave side the cell-divisions do not reach the centre, leaving a space for the common body, which has been shown by Barrande and Geinitz to produce a central longitudinal prominence.

In these forms the mode of development has been similar to that already explained, the modification being chiefly in the external position of the axis and the joining of cell-divisions with the axis on one side; leaving the common body in a somewhat triangular form, from which the alveoles are developed on either side.

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Whether the Phyllograptus existed as simple stipes with four ranges of cellules, or in a compound arrangement as in Retiograptus, the mode of development has been similar: either the germ with its initial point developed a single stipe with four ranges of cellules, or the same elements first subdivided, and each division gave origin to its stipe through the common body.

In regard to the development of the cellules in the different parts of the graptolite, we observe, as a uniform feature, their lesser development towards the base of the stipe. In all the monoprionidian forms this char- acter is particularly observable ; and in a few species the earlier cellules are raised in a scarcely perceptible elevation above the general surface of the common envelope. Indeed in a few instances it is impossible to ascer- tain satisfactorily whether these earlier prominences are expanded into open cellules. As the stipe is extended, they become gradually more and more prominent, until towards the middle, or oftener perhaps nearer the distal extremity, their greatest degree of development is reached. In some species this takes place near the base, and in the more elongated stipes there is no sensible increase throughout a great part of their length, and the two margins of the stipe are essentially parallel. ‘Towards the distal extremity there is a gradual, or often a more abrupt, diminution in the size of the cellules, and a few of the last ones are much smaller, until the ter- minal cellule is sometimes seen in a partially developed condition between the common body and the partition of the preceding cellule.

The same condition of development in the cellules is true of the diprio- nidian forms, as is shown in some degree in G. pristiniformis, plate xiii, but more especially in the accompanying figures of G. pristis and G. Whitfieldi, the last of which shows the higher cellules diminished, so as to contract the width of the stipe above (figs. 30 and 31, p. 86).

In fetiolites and Retiograptus, the full development of the cellules takes place below the middle of the length of the stipe, while they are less developed towards either extremity. In some species of fetiolites, including one from the Clinton formation, the cellules acquire their greatest development near the base, and the margins are essentially parallel for the greater part of their length.

In Phyllograptus, the lesser development of the cellules at the base of the stipe is a marked feature. They increase rapidly towards the middle ; and their greatest development is sometimes above and sometimes below the middle, but im all cases becomes rapidly less towards the apex.

In Dendrograptus, where we have a stout stem without cellules, the branches usually begin at some distance above the base: and in their lower part they have scarcely the appearance of being celluliferous ; in the middle of their extent the cellules become more distinct, and so far as can be observed they are less developed towards the extremities.

C

(di) ee)

CANADIAN FOSSILS.

§ V.—MODE OF EXISTENCE.

he numerous individuals of entire or nearly entire fronds illustrated in this memoir, as well as Jarge numbers of others examined, serve to give a pretty clear idea of the general form of the true Graptolites, as well as of their congeners of the same family. Notwithstanding the presence of the radicle or initial point observable in so many species, it does not afford evidence of attachment to the sea-bottom or to some other sub- stance, at least in the mature condition. In all the monoprionidian forms, however much or little extended the radicle may be, it is always smooth, and tapering to a pomt. In many of these, and more especially in those with a central disc, this radicle is reduced to a minute protuberance, and is often scarcely or not at all perceptible.

The same is essentially true of the greater number of diprionidian forms examined. In these the solid axis is sometimes extended beyond the base of the stipe, and terminated as if broken off abruptly ; while there is often a slender oblique process on each side of the base.

In Retiograptus and Phylloyraptus there is not the same evidence of completeness at the base of the radicle. The lower termination, when it can be fully examined, is broken, as if there had been a further continua- tion of this part, though it exhibits no enlargement. I have inferred that all these, like the example of Retiograptus eucharis (fig. 9, pl. xiv), have constituted parts of a similar compound body, and are bué the separ rated stipes of the frond. If this be true, their mode of existence is not unlike the other species with compound fronds and a central disc.

In G. bicornis the extension of the solid axis below the base of the stipe is not always preserved ; but when it is entire, we find two strong, diverging and slightly curving processes or spines from the base, having smooth terminations. Sometimes a dise or bulb, of the same substance as the stipe, extends between these spines, and in the compressed condition envelopes a few of the lower cellules, as shown in fig. 17, plate A. Some of the phases presented by the basal extremities of this species are shown in figs. 18, 15, 16, and 17 of the same plate.

The expansion at the base of this species has the same general appear- ance as the central dise of G. Logani, G. Headi, and others ; showing that this sort of development of the substance is not alone characteristic of those forms having several stipes united at the base. In other examples this basal expansion is contracted in such a manner as to give a crescent- form to the lower extremity ; but in all these gradations, the margins of this part are entire and unbroken.

We have seen that the youngest forms of the diprionidian graptolites, those which we may suppose had but recently escaped from the reproduc-

GRAPTOLITES. 39

tive sac, are furnished with the minute radicle-like appendage or extension of the solid axis, as well as the oblique lateral processes like tentacula ; and the condition of these parts does not seem to have been essentially changed during any subsequent period of their growth. While the extension of this slender solid axis does not seem of sufficient strength to have formed the base of attachment to the sea-bottom, it may have been sufficient to maintain connection with other parts of a compound frond.

For all those species with a single range of cellules, as well as for some with a double range, including Retiohtes, Retiograptus, and Phyllograptus, I conceive that we have already shown a similar plan of development and a uniform mode of existence; and we are constrained to believe that all these forms, in their mature condition, were free floating bodies in the Silurian seas.

In regard to another group including Dendrograptus, Callograptus, and Dictyonema, as well as one or two other forms, we have some evidence indicative of a different mode of existence. The stems of Dendrograptus are enlarged towards their base, and sometimes present a sudden expansion or bulb, which I have inferred may be the base or root, once attached to another substance or imbedded in the mud. The general form of the species conduces to the belief that they were fixed to the sea-bottom, though possibly this basal expansion may have resembled that of Graptol- thus bicornis. In most of the species described, the lower a is imperfect, and its termination unknown.

Tn those which I have termed Callograptus, the bases of the fronds are imperfect, but indicate, according to analogy, a radicle or point of attach- ment like Dendrograptus. In the more nearly entire forms of Dictyonema known, we have not been able to observe the base; but from their simi- larity in form and mode of growth to Fenestella and Retepora, we have inferred their attachment either to the sea-bottom or to foreign bodies.

Nearly all these forms occur in rocks where there are few of the larger fossils of any kind except the graptolites; so that there is little chance of finding their bases attached to shells and corals, as we do those of the bryozoans, even if they had thus existed, The Dictyoneme of the Niagara, Upper Helderberg, and. Hamilton groups do occur in strata which contain large numbers of other fossils ;. but we have no evidence of their having been attached. It is only from their general form therefore, and from their analogy with other bodies, that we infer that these genera may have been attached to the sea-bottom or to some objects during their growth.

_ We admit therefore that the family of Graptolitidz, as now dstertioal may include both free and fixed forms.

40 CANADIAN FOSSILS.

§ VI.—GENERAL CHARACTERS OF THE FAMILY OF GRAPTOLITIDH; WITH REFERENCE TO THE DISTINCTIVE FEATURES OF THE GENERA, AS KNOWN IN THE GEOLOGICAL FORMATIONS OF CANADA AND THE UNITED STATES.

In the first section of this memoir, I have remarked upon the nature and general form of the graptolites proper, and the allied genera which I regard as belonging to the same family. The large accession to the number of species, and the great variety of new forms added to those formerly known, require an extension of the characters heretofore given.

The numerous graptolites described by Nilsson, Hisinger, Bronn, Murchison, Hichwald, Portlock, Geinitz, Barrande, Suess, McCoy, Salter, Harkness, Nicol, Meneghini, myself, and others, were for the most part ina fragmentary condition, affording knowledge only of the simple stipe, the structure of its parts, and the arrangement of the cellules. From these fragments however we have derived the generic characters; while the modi- fications in form, and the order and relations of cellules, have furnished means of specific distinction in the greater proportion of those described.

In maintaining the generic term Graptolithus for the forms which have the nearest relations with those to which the term was originally applied by Linnzus, M. Barrande has proposed two sub-genera, characterized by the presence of a single series, or of two parallel series of cellules, under the names of Monoprion and Diprion. The latter term haying been applied to a genus of insects, the name Diplograptus* of McCoy has generally been adopted.

The distinction indicated would at one time have expressed a character perfectly trenchant ; but the discovery of such forms as G. ramosus ¢ and G. furcatus, shows the occurrence of both a single and a double series of cellules upon the same stipe, or, more properly, shows the basal portion consisting of a stipe, with two parallel ranges of cellules. The stipe, dividmg at some distance above its origin, is continued as two simple stipes, each with a single range of cellules. These cellules are on the outer margin, and are a continuation without interruption from those of the lower part of the stipe. Including these therefore in the same group with G. pristis, the subdivision indicated would have less value for the purposes of study ; but I believe these latter forms may be separated on other grounds, as will be shown farther on; so that with our present knowledge we may still

* In the genera proposed by myself, I have chosen the termination grapius instead of grapsus, since the latter termination is in use in the nomenclature of crustacea.

+ The subdivision of this species beyond the first bifurcation, represented in the Pale- ontology of New York, vol. i, pl. Ixxiii, fig. 3, is erroneous; the specimen consists of two individuals, the base of one being placed directly in the axil of the other.

GRAPTOLITES. 41

recognize Diprion, = Diplograptus, as a well-marked and clearly-defined sub-generic group of the Graptolithus proper, having such forms as G. pristis among the typical species.

Mr. Geinitz has more recently proposed the name Monograptus to include Monoprion and Rastrites of Barrande ; placing under this genus, as his typical species, G. sagittarius of Hisinger, which is the typical form of Graptolithus of Linneeus.

The genus Cladograptus* is also proposed by Mr. Geinitz, to include the species G. ramosus and G. furcatus, Hall, G. Murchisoni, Beck, G. serra, Brong., G. Forchhammeri, Geinitz, and G. sextans and G.. serra- tulus, Hall. At the same time the British paleeontologists, adopting the name Didymograptus, McCoy, place under that genus G. Murchisoni, Beck, G. caduceus, Salter, G. sextans, Hall, G. geminus, Hisinger, G. hirundo, Salter, and other similar forms. Those which are made the typical forms of the genus by Geinitz are the “species gemelle” of Bronn, who included under that term the G. geminus, Hisinger, and G. Murchisoni, Beck, which are by no means nearly related to G. ramosus or G. furcatus. The first-named two species, which were the earliest known of that character, and regarded as the typical forms of Didymo- graptus, are similar to G. bifidus and G. extenuatus of this memoir, which differ from the other species on plates i, ii, and ii, only in the lesser divergence of the stipes.

Very recently Mr. Salter has proposed a further subdivision of the graptolites under the name Jetragraptus, ‘a kind of double Didymograp- tus,’ of which G. bryonoides is made the typical species ; and G. quad- ribrachiatus is referred to the same genus. He also proposes Dichograp- tus for those having the “fronds repeatedly dichotomous from a short basal stipe mto eight, sixteen, twenty-four, or more branches, each with a single row of cells.”’ “ But the main character which distinguishes Dichograptus is the presence of a corneous plate | which envelopes all the lower part of the branches, and which is not known in any other genus of the group; it has not indeed been seen in more than two or three species of Dichograptus, but it may not in all cases have been pre- served.’

These subdivisions may be of some value when the entire frond and all its appendages are preserved, but unfortunately this is rarely so; and when we have but fragments of the stipes or branches, there is no force

* CuapoGRApsus, Geinitz. Syn. Graptolithus auctorum ; species gemelle, Bronn. (Die Versteinerungen der Grauwacken formation in Sachsen, etc. Heft. i, Graptolithen, p.29.) Monocrapsvs, id., ibid., p. 42. Syn. Monoprion et Rastrites, Barrande; Graptolithus, Suess.

{ First discovered in the graptolites of the Quebec group at Point Lévis.

t Quarterly Journal of the Geological Society, vol. xix, p. 136.

42 CANADIAN FOSSILS.

or value in the application of these terms: we are thus reduced to the necessity of adopting the old term Graptolithus. Again, the value of Didymograptus I conceive to be pretty well illustrated in the case of G. caduceus, the original of which is cited from Lauzon, Canada.* After studying the large collections of graptolites made by the Canadian Geo- logical Survey, I am compelled to believe that the G. caduceus was founded upon such forms as I have represented on plate xvi, figs. 22, 23, and 24 ; for we have no two-stiped species or forms of “‘ Didymograptus”’ with a pedicle or radicle so long as that represented in the figures of Mr. Salter, nor any one so abruptly recurved; and I regard the apparent radicle in the two examples figured as simply one of the four stipes imbedded in the shale, and exhibiting its non-celluliferous margin and a small portion of its width, as I have shown in the figures cited.

Other varieties of this form show only the two simple stipes, with a slight process in the centre. We have therefore a “‘ Zetragraptus” na condition undistinguishable from a ‘* Didymograptus’’; and the same may happen in G. bryonoides, as shown in plate iv, fig. 5, where the quadri- partite stipe is separated into two; and in the separated stipes it is mpos- sible to know if there have been two, four, or eight in the entire indi- ‘idual. With regard to those fronds which are repeatedly dichotomous, forming the genus Dichograptus, of which the distinguishing character is the central ‘‘ corneous plate which envelopes all the lower part of the branches,’ we may remark, that we have three or four species of the four-stiped form, or “* Zetragraptus” with the central corneous plate ; while we have four species which are not known to possess it. Of the two eight-stiped species known, one has the central corneous plate or dise, and the other was probably destitute of such an appendage. In G. Logani, with its numerous simple stipes, the central corneous plate is usually present, though not in all examples; while G. multefasciatus, with more numerous simple stipes than G. Logani, is not known to have a central corneous disc, and, from its mode of growth, probably never possessed such an appendage. From the irregularity of growth in the G. abnormis, I infer that there was no central plate.

In all the properly-branching species where the initial point is known, as in G. flexilis, G. rigidus, and G. Milesi, no such central plate has ever been seen; nor has it been shown in any European species, so far as I know. The frequently-bifurcating stipes, similar to the one originally proposed by Mr. Salter}t as the type of Dichograptus, are not known to possess the central corneous disc.

Although entirely willing to accept and adopt such subdivisions of the graptolites as will aid in determining their zoological character and

‘

* Graptolithus caduceus, Salter; Quarterly Journal of the Geol. Society, vol. ix. } Geologist, vol. iv, p. 74, 1861.

GRAPTOLITES. | AS

relations, their geological value, or indications of differences in mode of development, I do not appreciate at the present time the force and value of the proposed generic subdivisions for the two, four, and eight-stiped species, or the presence or absence of a central corneous disc as indicating generic distinctions; since it is impossible to obtaim any aid from such designations for the references of the numerous fragments which are the ordinary form and condition in which we find the graptolites, and in which they must generally be studied.

The form, mode of growth, and arrangement of cellules im all these several proposed genera, are so identical in plan as to afford no means for generic separation ; and although the same is true of the properly-ramose forms, yet I conceive it might have been convenient to adopt a term (Dichograptus or Cladograptus) indicating the ramose character of the stipes, regarding as true branches only the subdivisions which take place after the commencement of the cellules.

The genus Wereograptus* of Geinitz, proposed by that author to include such forms as Wereites, Myrianites, and Nemertites of Murchison, and Nemapodia of Emmons, etc., can scarcely be admitted mto the family of Graptolitidse, since all the American species referred to the first three named genera have no texture or structure like graptolites, and (as I have elsewhere shown) appear to be referable to the tracks or trails of some marine worms or other animals upon the sea-bottom ; while MVema- podia is simply the trail of an existing slug upon the slightly lichen-covered surfaces of the slates.+

The genus Glossograptus of Emmons is founded upon a species of Diplograptus with ciliate appendages on the cell-margins ; and no char- acters are given to show its generic distinction. The typical species of Nemagraptus (NV. elegans) is apparently a part of an individual of Graptolithus gracilis, or of some similar species; while the relations of the second species of the genus (JV. capzllaris), an elongate, flexuous, filiform body with afew branches at irregular intervals, can scarcely be determined from the figure given.

The typical and only species of Staurograptus t of the same author is a very remarkable form of extremely minute proportions. Its mode of growth and subdivision of stipes, if accurately represented in the figure, are unlike anything known among this family of fossils, and it merits generic distinction.

* Nereograpsus: Die Verstein. Grauwacken formation, etc., Graptolithen, p. 27.

+ These markings can be easily removed from the surface of the laminee by washing with water; and they can be traced over the exposed surfaces of the edges of the successive lamine.

t Glossograpsus, Staurograpsus, Nemagrapsus: Emmons, American Geology, part ii, pages 108 and 109,

44 CANADIAN FOSSILS.

The term Diplograptus is properly applied to such forms as Graptoli- thus pristis, Hismger, G. palmeus, Barrande (excepting figs. 5 and 6), G. foliaceus, Murchison, and G. pristiniformis of this memoir; where the cellules are disposed in parallel ranges on the two sides of the central axis, and are of the same or similar form and arrangement with those of monoprionidian form G. sagzttarius, and with others of that type, in which we include all the species of the first nine plates of this memoir ; the reason for the proposed separation being in the double range of cellules only.

In the ordinary forms of Diplograptus (plate xiii, figs. 15-17), as in the ordinary monoprionidian types, the cellules are usually closely arranged, and overlapping each other for a part of their length. In a single species CG. putillus, from the Hudson River formation in Iowa), which has come under my observation in some well-preserved fragments, we have so far a modification of the general arrangement of the cellules that the apex of one barely reaches the base of the next succecding. The stipe is a strong elliptical tube with a flattened central solid axis, the line of which is marked on the exterior by a longitudinal undulating groove (fig. 10, pl. A). The surface is strongly striated transversely, and the sides studded with tubular cellules, which are alternately arranged. These cellules are sub-oval, flattened on the side adjoming the body of the graptolite, curving on the exterior free portion, and obliquely flat- tened at the base just above the aperture of the cellule next below, as shown in the profile view (fig. 11, plate A). The exterior test of the common body is swollen in oblique undulations in the direction of the base of the cellules, or where the individual buds take their origin; and the axis is curved towards the opposite side, as shown in fig. 10, plate A.

The transverse diameter of the stipe is about two-thirds as great as the longer diameter. The celluliferous face of the stipe shows broad elliptical depressions ; the lower side, for little more than half the height, being the sub- oval cell-aperture ; while the upper part is the semi-oval flattened area at the base of the next succeeding cellule, as shown in fig. 11, plate A. In this case the cellules are shown to be separate and distinct tubes, closely pressed against the lateral walls of the stipe on one side, and communica- ting with the common canal by a slightly narrowed passage, as shown in figure 12, plate A, which represents a longitudinal section of the body. In a transverse direction the base of the cellule is wider than the aperture Cig: dd, spl. A):

Specimens of this character, on becoming flattened, would present a form where the cellules, though inclined against the common body, would not overlap each other, and where the margin of the cellule is directed backward instead of forward. Were these cellules to be prolonged, they would overlap the next in advance, presenting in this condition but a slight modification of the usual forms of Diplograptus. These deviations from

GRAPTOLITES. 45

typical forms are so slight as to offer no sufficient ground for generic separation.

There are however a few examples, where the stipe is marked by a range of cellules upon each side of the central axis, which appear to be properly separated from Diplograptus, on account of the form and structure of the cellules. These are apparently quite unlike those of G. pristis, and others of that sub-genus. The Graptolithus bicornis, and two or three allied forms, when flattened in the shale, show, as already described, a simple semi-elliptical notch in the margin of the stipe, nearly rectangular to the axis. This is well shown in fig. 3, plate vi, of M. Rarrande’s memoir, and also in Mr. Salter’s illustrations of Graptolithus teretiusculus of Hisinger.* It is represented, less perfectly, in the figures of Prof. Harkness,j and in most of my own figures on plate lxxii of the first volume of the Paleontology of New-York. When compressed rectangularly to the cellules, the apertures are transversely oblong-oval ; and the same form is shown when looking upon the celluliferous margin of an uncom- pressed stipe.

The structure of these stipes and their cellules has already been described in a preceding section, with reference to the figures illustrating the same. The G. bicornis, renin im New-York and Canada, may be considered the type cf a group of species of which we have two in the shales of Norman’s Kill near Albany, one in Ohio, and a similar or identical form in the Utica slate at Collingwood in Canada West. I would include in the same group figs. 5 and 6 of plate iii, as well as figs. 7, 8, and 15, plate 11 of M. Barrande’s Memoir; Graptolithus teretiusculus of Hisinger ; and those referred to the same species by Salter.t The Diplograptus rectangularis of McCoy |] is of the same type, as also figs. 1, 5, 10, 11, 12, etc., tab. ii, of Geinitz (Graptolithen) ; and I conceive that

many, if not all of the scalariform specimens, belong to species of this character.

The Graptolithus ramosus has usually been arranged by authors under Diplograptus ; the lower part of the stipe having a double range of cellules, while it is bifurcated above, with the cellules on the outer margin of each division, as already described; and a simple explanation of this condition has been offered by supposing that the solid axis has been separated after the death of the zoophyte. This however will scarcely afford a satisfactory argument when we find that all the specimens are in the same condition ; that usually the division begins at a uniform distance from the base ; and that, when entire, the divided portion much exceeds the

* Quarterly Journal of the Geol. Society of London, vol. viii, pl. xxi, figs. 3 and 4. { Id. Ibid., vol. vii, pl. i, fig. 11.

ft Quarterly Journal of the Geological Society, vol. viii, pl. xxi.

|| British Paleeozoic Fossils, page 8, pl. xiii, figs. 8, 9, and 10.

46 CANADIAN FOSSILS.

simple undivided part of the stipe. Moreover, the species is recognized in this condition m the Hudson River formation in Canada, and has like- wise been recognized in Great Britain ; while a similar or identical form has-been shown by Prof. McCoy to occur in Australia. We must there- fore seek some other than an accidental cause for the explanation of this uniform bifurcation of the stipes of that species. In the meantime, it appears to me highly proper to suggest its separation from Diplograptus.

On farther comparison, we shall find that G'. ramosus is not quite alone in its peculiar characters. In G. furcatus there are a few cellules at the base of a simple stipe below its bifurcation ; and in G. sextans, the lower part of the stipe is simple, the division taking place above the first cellule ; but in entire individuals the division is never from the initial point, as we see it in G. bifidus and G. nitidus of this memoir.

Now these first-named species, as well as G. ramosus, have cellules of a peculiar form ; and looking still farther, we find a similar form of cellule in G. Lorchhammert, Geinitz, and G. divaricatus, Hall, two species which are divided from the base, having a single range of cellules upon the outer sides of the stipe. I believe it will be found, moreover, that all the graptolites with cellules on the lower side of the stipes (in reference to the initial point or radicle) have these parts of the same form as G. ramosus, and very unlike the G. pristis and allied species. Nor are the cellules on the simple or divided portions of the same stipe, or on those which are entirely divided and upon the lower side, at all like the cellules of G. priodon, - G. geminus, G. Murchison, or any of the allied forms illustrated in this memoir, to which the term Didymograptus has been applied ; nor can they be properly united with them. ‘The form of the cellules is always suffi- ciently distinctive even in fragments of the stipes; and this feature, together with the mode of development or growth, seems to me sufficient to sustam a generic distinction.

The genus /tetiolites is described by M. Barrande as having no central solid axis, but with a single internal canal occupying the median portion of the polyp. The prevailing form of the stipe is somewhat concayvo- convex, with the centre of the concave side prominent; the entire surface. is covered by a net-work of corneous substance, and the cell-apertures are quadrangular.

Prof. Geinitz has given some further illustrations, showing more em- phatically a longitudinal axis on the convex side, to which are joined the ceell-partitions ; while he regards the common body as occupying the prominent central portion of the concave face of the stipe, and shows the cell-partitions terminating before reaching the centre, leaving a space occupied by the width of the common body. This he represents as covered by a net-work of slightly different texture from that of the other portions of the substance.

GRAPTOLITES. 47

The Canadian specimens which I have referred to this genus are so extremely attenuated that it is impossible to determine the details of structure, and the surface-characters are obscure. ‘Thus far we have no American specimens in a condition to afford the means of elucidating some obscurities which seem to me still to exist in regard to the intimate structure of this genus. The species of the Clinton formation is extremely compressed ; and while some specimens show the cell-divisions termmating at a distance from the centre, yet, after protracted and repeated exami- nations, my most critical observations result in showing only the struc- ture which is illustrated on plate B, figs. 20 and 21.

On one side we have an external, cylindrical, solid axis, to which the

cell-divisions are joied; but these latter show only filiform cylindroid - processes, extending from the axis to the cell-margin, and projecting a little beyond the margin of the stipe. The only other aspect which we observe in this species is that of an undulating or zigzag filiform axis on the opposite side, to which the cell-partitions are joined, as in fig. 21, plate B. We know this to be on the opposite side or within the stipe, as it is sometimes seen overlying the straight axis and cell-partitions. _ At the junction of the cell-divisions with the zigzag axis there are other processes of similar character, projecting upward and outward from the ‘axis, all of nearly equal length, but apparently broken at their extremi- ties. J have not been able to determine any connection between these and other parts of the skeleton, but we have the two structures very clearly represented in the figures referred to. I have supposed that similar processes may have extended to the opposite side, from the junc- tion of the cell-partitions with this undulating axis, either joining the cell-divisions or the straight axis; but after long mvestigation I have been unable to find satisfactory evidence of such connection. The cell-apertures are surrounded by thickened margins, and the only appearances of cell- partitions are the sub-external cylindrical extensions from the aperture to the axis. Neither the species of the Quebec group nor that of the Clinton formation, in any of the specimens seen, are in a condition to show evidence of the concavo-convex character of the stipe represented by M. Barrande and Prof. Geinitz.

The species of Retograptus, while having some characters in common with Ketiolites, do not possess the reticulated structure of the test in either of the described species. There yet remains some obscurity in regard to the internal structure of this genus, which can only be satisfactorily explained by the examination of better-preserved specimens. Neverthe- less, in its general form, structure, and mode of growth, it is shown to be quite distinct from other graptolitic genera. The three species referred to this genus present differences which can only be reconciled by supposing that the two sides of the stipe are very unlike each other in form and external characters, as in [etiolites. -

48 CANADIAN FOSSILS.

The species for which I have proposed the genus Phyllograptus, pre- sent close analogies with the typical form of Diplograptus in the character of test and form of cellules. These, in their aperture and form, are nearly quadrangular; and the cell-partitions are apparently continuous between the cellules, and reach nearly to the central axis ; characters which we find in Diplograptus. These forms, in their great lateral extension, depart widely from their analogues; but they differ more essentially in their cruciform mode of growth, presenting an arrangement of parts, as if four simple stipes (like those of G. bryonoides or G. Bigsbyi) were joined together by the coalescing of the solid axes. In this latter respect, and in their great development in width, they differ most essentially from all the other genera of this family of fossils. ‘These forms are fully illustrated on plates xv and xvi of this memoir.

In the typical species of Dendrograptus, as illustrated under the generic description, and in some of the species on plate xvii, we have a wide departure from the typical forms of Graptholithus, as developed in the characteristic species of the genus (plates i-ix). The strong stem or trunk, which is free from cellules, and which has apparently been fixed at the base; the irregular branching, which has no bilateral, and apparently no definite arrangement, such as observed in all the forms of tree Grap- tolithus, are strong points of dissimilarity, and furnish characters for generic distinction. The stem and branches are unequally striated longi- tudinally, but the form of the celluliferous branches and of the cellules offers no important difference (except in the smaller dimensions) from those of the stipes or branches of the usual form of graptolites with a single series of cellules. In one species referred to this genus (the D. gracilis) there is some departure from the typical form of cellules, and the body of the stipe is contracted at intervals, while the form of cellule and cell-aperture is not unlike some of the Sertularians.

The genus Callograptus offers forms which are intermediate between true Dendrograptus and Dictyonema. In these species, the forms of the cellules have not been fully determined. ‘They are marked in one species by slight oval pustules, or oval depressions, upon the extremely compressed surface of the stipe; but it cannot be satisfactorily shown that this appear- ance indicates the normal condition of the cellule or the aperture. If the true form be in reality so far different from the usual character of the Graptolitidee as these appearances indicate, it may be found necessary to separate them from this family.

The genus Dictyonema is restricted to such forms as have the numerous stipes and branches connected by a transverse process, and the whole united in a flabelliform or funnel-shaped frond, without elongate stem or trunk. The stipes and branches are irregularly striated externally, con- sisting of a corneous envelope, as in ordinary graptolites; but I have not

GRAPTOLITES. 49

been able to determine clearly the existence of a solid axis. The cellules are indicated by angular processes or cell-denticles on the inner side of the branches ; as shown in fig. 5 of plate B.

In the genus Rastrites of Barrande the distinguishing features are the slender cylindrical stipes or branches, with distant slender tubular cellules.

The few species of Zhamnograptus known consist of cylindrical or sub- cylindrical stipes, with slender elongate alternating pinnulz or branchlets. No evidence of cellules has been observed in any a the specimens.

The peculiar forms for which I have proposed the name Ptilograptus, consist of branching stems, which, in all their divisions, are studded on each side, in alternating order, with narrow pinnule. These are some- times extremely slender, or even capillary in their dimensions. In one species I have detected elliptical spots upon one face of the pinnule, which are slightly flattened, and I infer that these are the cell-apertures. The substance of the test is corneous, and there is an internal solid axis. Although I have placed these forms under the Graptolitide with some hesitation, the form of cellules may perhaps render a separation desirable ; but with only our present information, such a separation cannot at this time be made.

The genus Jnocaulis was proposed for some flattened stipes with a scab- rous surface, which have the appearance of denticles upon the margins. These stipes grow in close groups or tufts, and are bifurcating or branched in their upper portions. No positive evidence of cellules has been observed. The presence of denticles, together with a corneous or carbonaceous sub- stance, have induced me to place this fossil among the Graptolitide.

There is still another form known, which may be doubtfully classed among the Graptolitide. It consists of a slender flexible median rachis, on each side of which are placed, in alternating order, slender flattened pinnulz, which are of nearly equal width inomeboe and are themselves flexuous. Upon one side of the rachis are minute points or dots, which have apparently been the cell-apertures. The test is a black corneous or carbonaceous substance, but there is no evidence of a solid central axis. These bodies are numerous in some shaly beds of the age of the Trenton limestone, at Plattville, Wisconsin. For these I have proposed the name of Buthograptus.*

Associated with the preceding forms, there are some stems of corneous or carbonaceous texture, frequently branched, the branches again dividing, and sometimes, if not always, in whorls; in one of which six divisions were counted. The general form of the body is not unlike that of Den- drograptus, but the branches are more slender, and ramify in a different manner, while there are no visible cellules. ‘Without farther knowledge,

* Report of Progress of the Geological Survey of Wisconsin for 1860, p. 19; commu- nicated January Ist, 1861.

50 CANADIAN FOSSILS.

I refer these fossils, with hesitation, to the genus Oldhamia ( O. fruticosa,

Hall).

The variety of form and mode of development among the graptolites is shown, by these collections from the Quebec group, to be much greater than had ever before been supposed. ‘The number of species which have been traced to their origin, and whose mode of growth has been verified, is probably larger than in all the collections heretofore made ; and, together with those before known, enables us to give a very full exposition of the characters of this family of fossils.

SYNOPSIS OF THE GENERA OF GRAPTOLITIDA.

Te

Species consisting of stipes or fronds, with a bilateral arrangement of the parts ; a solid axis, with a common canal extending along each series of cellules,

1. The successive buds developed in tubular cellules, which are usually in contact for a greater or less pro- portion of their length, and inclined towards the axis.

a. Cellules in single series along one side of a com- mon solid axis. Stipes, two or more, from a com- mon’ origin, with or without a central disc. Sub- genera Monoprion,* Didymograptus, Monograptus, Tetragraptus, ete.

. Cellules on one side of slender branches, which are developed on one or two sides of a long slender axis or rachis, the free. extremities of which are likewise celluliferous. Hx. G. gracilis and G. diver- gens. |

c. Cellules developed in aie arrangement on two |

ao

GRAPTOLITHUS, Linneus.

sides of a common solid axis. Stipes narrow elon- gate. Sub-genus Diprion, = Diplograptus.

d. Cellules developed in a cruciform arrangement on the four sides of a common or coalescent axis. Stipes elliptical or sub-elliptical.

Puytiograptus, Hall,

2. Cell-apertures excavated in the margins of the stipes, without tubular or cup-form extension; the cell- apertures upon one or both sides of the stipe. Graptolithus bicornis and others.

Cumacograptus, Hall.

3. Solid axis eccentric or sub-exterior, with cellules de- veloped in parallel ranges on opposite sides of the stipe, and in contact throughout their entire length.

a. Known only as separate stipes, with reticulate test.

b. Occurring as simple stipes, and as compound fronds; test smooth.

} Retiotites, Barrande. } Retiogrartvus, Hall. * Should it be proved that there exist simple stipes with a single range of cellules,

the definition of this section will require to be modified, or a new sub-section made to include such forms.

GRAPTOLITES. 51

Il.

Species having a common trunk or stem, or growing in sessile groups of stipes from

a common origin, without distinct bilateral arrangement of the parts. Cellules in single series on one side of the stipes or branches, and arranged along a common canal or axis. 1. Branches free (i. e. not connected by transverse bars;)

cellules in contact or closely arranged. } Denprograptus, Hall.

bo

. Branches unfrequently and irregularly connected by

CALLOGR ph transverse processes. } craptus, Halé

OO

. Stipes and branches more or less regularly united in a

reticulate frond, without elongate stem. | Dictyonema, Hall.

4, Stipes round or flattened, growing in groups, and bifur- cating above; margins denticulate; surface rough or

: Inocautis, Hall. scaly. [The relations of this genus are not fully deter- om ,

mined. | III. Slender cylindrical branches, with tubular cellules arranged in single (or in double 1) series. Cellules not in contact in any part of their length. Rastrites, Barrande. Iv. Species having a common axis or rachis, with slender lateral alternating branchlets, Cellules unknown. THAMNOGRAPTUS, Hall, Vie

Species having a common axis, more or less frequently bifurcating, with pinnule closely and alternately arranged on the opposite sides; cell-apertures on one face of the pinnule. Prinograptus, Hall.

VI.

A simple flexuous rachis, with slender flexuous flattened pinnule arranged in alter-

nating order at close and regular intervals on the two sides. Cell-apertures unknown,

or circular. Burnoeraptus, Hall. , VII. Strong stems, which are numerously branched. Branches and branchlets slender, arranged in whorls. Cellules undetermined. OupHamia [7], Forbes.

§ VII.— GEOLOGICAL AND GEOGRAPHICAL DISTRIBUTION OF THE GRAPTO- LITES IN THE ROCKS OF CANADA AND THE UNITED STATES.

Until the remarkable discovery of the graptolites of Point Lévis in 1854, the chief repository of these fossils known in American rocks was in the shales of the Hudson River valley.

The position assigned to the rocks of the-udson River valley was the superior part of the lower division of the Silurian system. In this respect, the horizon of the Graptolite beds corresponded with those of Ireland, from which these fossils had been described by General Portlock ;* and with the position assigned to those in Sweden, as well as with those of the

* Geological Report on Londonderry, etc., page 317-322.

52 CANADIAN FOSSILS.

Llandeilo and Caradoc formations of Great Britain. The graptolites of Bohemia are from strata referred by M. Barrande to the base of the superior division of the Silurian system; and those of Saxony were regarded as from the same horizon.

In 1850, M. Barrande expressed the opinion that the epoch of the graptolites was posterior to that of the “ Faune Primordiale”’ in Bohe- mia and Scandinavia; while their association with primordial fossils in the Malvern Hills and at Snowdon, indicated the earlier appearance of these zoophytes in Great Britam. A comparison of all the published information on the subject at that time induced M. Barrande to conclude, as a general fact, that the graptolites had made their earliest appearance in the regions of the northwest; and that their highest development in central Europe had only been reached at a later period, or at the base of the upper division of the Silurian system.

The investigations in the Geological Survey of New-York had proved in a pretty satisfactory manner that no graptolites proper occurred above the horizon of the Clinton group, though Dictyonema (supposed to belong to the same family) had been found in the Niagara formation. The species at that time known ranged from the higher strata of the Lower Silurian, to the lower beds of the Upper Silurian division; and both in Europe and America, these fossils were regarded as of eminently Silurian character, and unknown in any later geological periods.

The discovery of a graptolitic species in the Potsdam sandstone of the St. Croix River valley, by Dr. H. A. Prout, in 1850, was the first indica- tion of the occurrence of this family of fossils at a lower horizon than that of the Hudson River and Trenton formations.

Before the discovery of graptolites in the shales of Point Lévis, these rocks were supposed to belong to the age of the Hudson River formation ; and although it was shown that the graptolites were all of different species from those previously described, yet they appeared to offer only corrobo- rative evidence in support of the previously entertained opinion regarding the age of the strata. It was only at a later period, and from the dis- covery of numerous other fossils in the same formation, some of them having a primordial aspect, that its higher antiquity was suspected.

The shales of Point Lévis, with their associated limestones and sand- stones, since termed the Quebec group, are now regarded as embracing the period from the Calciferous sandstone to the Chazy limestone, inclusive. This epoch therefore is entirely anterior to that of the Hudson River formation, and a careful comparison of all the species of graptolites has shown that no identical species occur in the two series of rocks.

In the present state of our knowledge, we recognize the Graptolitidee as beginning their existence at the period of the Potsdam sandstone. The greatest development of the family, both in genera and species, is

GRAPTOLITES. 53

found to be at the epoch of the Quebec group. Several genera and a few species are known in the Trenton formation; and a greater develop- ment, embracing most of the genera and many species, occurs at the period of the Hudson River formation in Canada and the United States. In the Clinton strata we have a single species of Graptolithus, and a Retio- lites ; while Dictyonema and Jnocaulis occur in the Niagara beds. In all the subsequent geological formations we have found no true graptolites, and the only representatives of the family consist of fragments of Dictyo- nema, belonging to a few species. ‘These occur in the Upper Helderberg and Hamilton formations, above which we do not yet know a species of any genus referable to this family of fossils. The genus Graptolithus has its upper limit in the shales of the Clinton formation, and all others of the family, except Dictyonema, are restricted to the Silurian system. —

The geographical distribution of the Graptolitide is not in all respects coincident with the extent of the geological formations. Dendrograptus occurs in the Potsdam sandstone of the St. Croix valley; but neither this nor any other graptolite is known in other localities of the sand- stone, so far as I am-aware. ‘The species of the Quebec group, number- ing more than all the other formations together, have been identified for a longitudinal extent of about 900 miles; Point Lévis, Orleans Island, St. Anne’s River (Gaspé), and the western part of Newfoundland, being the principal localities. But although the Quebec group is known to extend into Vermont and along the eastern counties of New-York, I am not aware that graptolites have been found in any authentic localities of that formation.* Thus far, therefore, these fossils of the group are known only in Canada and Newfoundland.

The Trenton limestone, while furnishing two species of Graptolithus in New-York, gives at the west no specimens of the genus proper; but we have one Dictyonema, a Buthograptus, and an Oldhamia?t im the same formation in Wisconsin, though not elsewhere known.

The Utica slate at Utica abounds in the remains of graptolites, and these fossils are of frequent occurrence at Oxtungo Creek, in the valley of the Mohawk. It is probable that some of the localities referred to the Hudson River formation, may be in the Utica slate, which, owing to the disturbed condition of the strata, is not separable from the succeeding slates.

In the Hudson River formation, the characteristic graptolites, of numerous species, have been found, in greater numbers than elsewhere, at Norman’s Kill near Albany ; but they occur at Stuyvesant’s Landing, and at the

* A single branching form, the G. Milesi, has been published in the Geological Re- port of Vermont. The specimen was found in a boulder of slate, but it is probably of the Quebec group. [

D

54 CANADIAN FOSSILS.

city of Hudson; while some species have been found near Baker’s Falls on the Hudson River,‘and at Ballston and Saratoga, New-York. Grap- tolites of species identical and similar to those of the Hudson River for- mation have been found by Dr. Emmons in the shales of Augusta County, Virginia, and also in Tennessee.

The more characteristic species of the formation, G. pristis, G. bicornis, G. ramosus, G. sextans, G. divaricatus, and G. gracilis, have been recognized among the collections of the Canada Geological Survey, from the Hudson River formation in the valley of the St. Lawrence. In the extension of this formation westward, a few species only have been found in central and western New-York ; among these, G. pristis is the most com- mon, while G. d¢cecrnis is more rarely seen. In Ohio, we have no more than two species from rocks of this formation ; while extensive collections from the same formation in Wisconsin and Iowa have afforded only three species (all unlike those from Cincinnati), and one of these has been found in beds of the same age in Illinois. In the catalogue of fossils appended to the Geological Report of Missouri, no mention is made of the occurrence of Graptolitidze in any of the formations.

The great accumulation of materials at the epoch of the Hudson River formation has been in the direction from northeast to southwest ; and along this line the black and dark colored graptolite schists, alternating with coarser beds, have collected in much greater mass than in any other part of its extent. In the northwestern counties of New-York, Jefferson and Oswego, where the formation has a thickness of more than a thousand feet, the graptolites are comparatively few in species, and not of common occur- rence. The gradual attenuation of the rocks of this formation towards the west is marked by the extreme paucity of graptolitic forms.

The graptolites of the Clinton strata have not, to my knowledge, been found beyond the limits of western New-York ; and both their horizontal and vertical range is very restricted. The graptolitic forms of the Niagara formation (Dictyonema and Inocaulis) are very limited in their geographical extent.

The Dietyonema of the Upper Helderberg and Hamilton formations are known to occur in New-York and in Ohio; and in the northwest a species has been found in the Upper Helderberg limestone on Mackinac Island.

This distribution of the Graptolitidze, as well as their general association with other fossils, together with the nature of the sediments, would indi-

cate the proximity of the coast-line as their habitat, and as the zone of their greatest development.

GRAPTOLITES. 55

TABLE SHOWING THE VERTICAL DISTRIBUTION OF THE GENERA OF THE FAMILY OF GRAPTOLITIDE.

R) 2 oO o0| ap 4 5 ale oS 2|\2 : man ae oa oI 8 \o |S al epl.© BIE Idlgl/slalsia=imisis|s Si So tas] Hig ~lislid ols Ble S g/2 SS } a eI g [o) naloNSlg N).5 = 6o| 2 o ie) ia & © |S | ).8 aio E ei vile OSA Hl S| OS |slo a) s/o) BIOOIB (DS lO le Ol4 |p lq |O|o ah eee Sub-genus Monoprion .......-[..| x |a|sl.-|x a ' RAPTOLITHUS, 9 Sub-genus Diplograptus...-../..| x |x| iC ve GIIMAGOGRARTUS*scceiete dscns coe plelc tenes SSSR Shale lise salle. RE a I evAHEA GU RINPNUTS Seoteretctetaroteteleltiei che: eletiorer si ciecereyausye creultorerl MSee ithe Mine lle: cillesesfeveilfaveillecallarsiiis ail eyaclre

FUENEEONTMMSe eaeretat leveled sieiotets sels ete sivtuigerensreree secratonott Sets WD a Ve wilese Ivele alee Meiiace loetiee AERC) CAMELS tetalalefale) sustelelale) ate ele)leiricrsiare/e =)s/e) sfelsiel|ieve | 5 i

DENDROGRAPTUS .-.+-sees med apetelcate eta n ave rataxtes cues eral Spe See Pavel le ces d fore aes fay l tee Pare fares easel ails QATTOERAPINUR) 4oHo coo OUdd DUDDDOOOU DOUDIAO DC nial lmcon isla| ees or pele IDiOT WON. jn cagoopon bouoT Good oDdonddoEoodS Bila? #

PTH OELAPTUTEL A ocac bo domoooodanonod Goddocdallnalyce EPAWENOG HAUT US) s\alsabel elieleba le siniele)oiaele/ aia =| e's/elele) ee live | SC. Illa 01|/5%

Schoo) Sale| sales |B RASTRITES ...+.0. Rast teletatardital settee Secee a aes Bocabitect He

IDROHABTRESS God pOb a0 CODD DOO COBO OC COUCIOCIOOIGG nai lacie areal aa ESUIBENGAIE LS tateveatel are falc’ shereleveletoleevan's evsie eveie elise ae at ae illo s QD nAITIN ? sions pacino COU MON O Gite Cite OCECCR COE RCI ieaen (-teymn ioal ope

The pre-eminence of the Quebec group, as the period of the greatest development in the Graptolitidee, is shown in the above table. Of the fifteen genera and one sub-genus here enumerated, eleven are known in this period ; while four genera, viz., Phyllograptus, Dendrograptus, Callo- graptus, and Ptilograptus, are not at present known in any higher position than the Quebec group, though one of them occurs in the Potsdam Sand- stone. All those genera having the nearest relations with Graptolithus proper occur in this group, and the species of that genus found in it are more numerous than in all the subsequent formations, so far as at present known.

In addition to circumstances originally favorable to their development and growth, the subsequent conditions presented during the period of the Quebec group in Canada seem to have been equally favorable to the preservation of graptolites, and in no other formation have they been found with all their parts so entire.

* Under this genus, in the following table I have introduced a sub-genus, Dicrano- graptus.

56

CANADIAN FOSSILS.

TABLE SHOWING THE GEOLOGICAL DISTRIBUTION OF THE SPECIES OF GRAPTOLITIDA IN CANADA AND THE UNITED STATES.

Genus Grapro.ituus, Linnzeus. (Sub-genus Monoprion, Barrande.) G. abnormis,

GENERA AND SPECIES.

alatus, arcuatus, bifidus, Bigsbyi, bryonoides, Clintonensis, constrictus, crucifer, denticulatus, divergens, extensus, extenuatus, flaccidus, f flexilis, fruticosus, gracilis, Headi, indentus, Logani, Logani, var., Milesi,t multifasciatus, nitidus, octobrachiatus, octonarius, patulus, pennatulus, quadribrachiatus, ramulus, Richardsoni, rigidus, sagittarius, serratulus, similis, tenuis,

angustifolius, ciliatus, inutilis, marcidus, mucronatus, peosta, pristis, pristiniformis, putillus, n.s.,

Hee See eee eee eee

| Potsdam.

seee rece eee esreseles

CC oe]

swPeeereeeeesseeveies

ee rece eeceneseneeies

eeeeeneesroeeteseseles

seeeseeesece eeecelies

seer eeeesceseesseles

eee esas cease eoenios

ee ee |

seoeeeee cece eeasiae

ee eeeeeeeseeseeries

SHCHIG TE) s easy s aye |'oe

HCE A eis eecel

FY bd bd bt tad bt

see eeeeecece

(Sub-genus Diptocraptus, McCoy.) G. amplexicaulis,

MEE es- cael.

, Quebec.

Calciferous, Chazy,

ate cle ate cle ale als a ee Om Oe

. Ov dals tatae® ate ste ate es . eS

ste ate Ed

se oe te ee wa ES A FT

ale as ~

al al al a) at al a) dk °* BKK RR eR KK,

%

Hudson River.

seles salee selee wales Pa i sealer

x o-| x eeoles wale aelee

eel %

% eel % Hie. oe | % ol %

* aol % ae | % oe | %

Niagara.

| Onondaga,

eeleclecion

eeleclee

£0} tip o|® £I8 a = Via Sls 2 ||] eo Simlola pul etl ales Viola! Elalala oe ee 4|p |B \o

eeleslerlee seleosles|ee saleeleetes weleclerlee celeclec|ae seleclerlen 8 elerlee saleclentes

| Carboniferous.

t Utica slate.

t From a boulder.

GRAPTOLITES. ot

TABLE SHOWING THE GEOLOGICAL DISTRIBUTION OF THE SPECIES OF GRAPTOLITIDR IN CanaDiA AND THE UNITED StTatges.—(Continued.)

S)

2

= =|

CS : els C

ewe Sant =| a 2]

GENERA AND SPECIES. a £ isle 5

g/2 clclelala(@F lees SIS s[slolslelsltelslels|2|s elo Slel2fslelalsle|els|ais SlSslflslSislelsie/Zisisls MOO|s |e [=O l4 lola ie loo

(Sub-genus Diptograptus, McCoy.)—(Con’d.)

Gi. (UAC RiMUGHOMNIMS TT le onocadooosadaDolool Go \lballPallecilbolled|lesieallaai[s allpalic secalinus, HBCON we. cs sicin loin aiailiem| em |en |= >| ete ls [a «lisse lore llerellle spinulosus, Bl So ances has Sune locas. (acl |e2solealaolleeltolsalsallsa.c Whitfieldi, Blococbo sooo scaboteall a6 |lsclle|ooloalloalac|bella ollacloulls (unnamed,) n. s. Sodb dab 5060 oUn6Ool|Dol| Gn lool|e8iad}icolloalloaliadios|iouiiaails

Genus Crimacocraprtus, Hall.

C. antennarius, Bl oagowoncdabooncallsoll $3" lloalloclloolballoallboleo|sollaoficallc bicornis, lsboo 6060 dogs saablloolli oo lloolS3lloalsclealloaliMolloallo cia ole parvus, n. s., lelSSooandouodd OD aolool) So jool(eelloollociasié allele slocllosiioc typicalis, n. s., lel condo soon deddollooll’ao |loalS|loollas|eollslloalidolloailooh ©

(Sub-genus Dicranograptus, Hall.)

_ C. divaricatus, 31a Hd Bac COOO CUED) Oc)| ec eal Gol oa) (aclolacle leis laelc furcatus, BI Gn cceS PeMmnOercalacr Sse onions icici aaalleallc ramosus, Bisse hastooneccraclog) Gs lseles)suSellecltulosiicn|aallsaic sextans, Tie leisjeiaie etn s slates [of aia) fale fates silmial anil atell tell <beletnl ede

Genus Puyiiograptus, Hall.

P. angustifolius, FELIS Sohn vel so aula efuis eet -se}|iW 2 8 f=/ai| ¢te\} «| eyo)|-1~1| veltavel| ell allisrallsie Anna, ihm OOO ROEU See Oa es joolaalonieolacldalealleiclioaleaioe ilicifolius, [elepcioe BpeEDe Sonal |Ool| call ecllod (calle ellarliacoe]oe)|eciion typus, lBleonnogooOUEHbo cel eolie2 salicc as Ise sHlacdiselloollediios

Genus Rertrouitrss, Barrande.

R. ensiformis, Milos Chao momen Den olocd lee o /AclGolne| Celie Mel lant ea itetel eel leee

venosus, Eos dob co done Gono od aS, Uldolloe nol eelladlealigetoulkalle cles Genus Retrograptus, Hall.

R. eucharis,t HEME javateh cYuties eve eiohcyaveoy| rei] are cen aol Sel etltes fay sitint afl anes faa) he eel oe Geintzianus, 15 ROME ROS DOUeM Oe CEO] ol larmn malic lok Eni plcelealiesl ine onl ec tentaculatus, PEL ite; o) sins at ohh Yao afetctai| o6i\) bee Hieve He icvedl aayl/< oilebel evened spa evel ae

Genus Drenprocraptous, Hall.

D. diffusus, LaLa oly Siac Cee ool | a |fie zed lolol easel eset oi ered lore are Cec se fo divergens, HE Teteresaleayoisercel cy ove ve avosen {iach SCRE Ite tovei| AIM lleva Theses ansillaves lleva erellbvcll ee erectus, TEL ees CCRT CCR NSS en eee Sal bam [ete at [| hae Pol tae flexuosus, DE pepeyen er creiiacm stay erates |utaql Sean tate feces [cue fiery Imeedl ites Latte alfeve [ae eas fruticosus, Tyran jatelaifeolerasiciers [ovat lave [lavelltve lacie: alloo|jsollon gracilis, MTree oticnsy evaiiaseva evar eecss | fare i Sek lleva eve raved Rete [revel Srasltorcelbeesd Patel le al lave Hallianus, IPO, GooDaoOO Rone oolloall eallaullsedaoloslaalleolicclanilca striatus, ME Heyeea pete a} vena af aoh-avoyeted (rss a: seine ates tava, ep lhoeesl eucal nuedleeat lees! eveell see I ee

Genus CaLuocraptus, Hall. C. elegans, MEV ere he a fohe sever ehey se aye eter fea SEM ar separ exes Pa (Ue Pay) US 2 ai te

Salteri, AE LWapekeveyevstiay a atch avasayesey ai Peis ae Sete [ Sao | evar Seal tceastlsiell Geer eaitieeal eSeSLES

+ Utica slate. f Utica slate, Lake St. John.

58 CANADIAN FOSSILS.

TABLE SHOWING THE GEOLOGICAL DISTRIBUTION OF THE SPECIES OF GRAPTOLITIDAR In CANADA AND THE Unitep Stares.—(Continued.)

)

o

2

o

=}

oS IN

GENERA AND SPECIES. cy a ke) Els on

Threag

2/2

o|;s a (OO

Genus Dictyonema, Hall.

D. cadens, n.s., Pivots bis dae sinicemece aol 4 fenestrata, Breiee etd erate ie leteveialaeif sail) tet gracilis, Ui ReGsnt Ob aebocsery Kgl boc amino aniBsy (Ek cicie seicicin mre inievelels iafel] ate irregularis, ELichaia\ > aretatorera siaverrierel| sta] ae Murrayi, EL taie Cratelntes thoi a ioretall teil Ae Neenah, Ub Gopae ogacco 2aa6lboll oo quadrangularis, EDs areter foto aterctonetcroter hel ese retiformis, lls cone do goNoaee|lool|-oc Websteri,t EL yeraintatciere tereretarctete leh ets

Genus Pritrocrartus, Hall.

P. Geinitzianus, TD. cierto ce ses) aeiaraia wiaredl mee ge plumosus, latroanaduoodocecpalool! &

Genus THamnocraptvs, Hall.

T. Anna, 13ieaeriocoodocomaas| oll <3

capillaris, Elistars siactesiticlers

typus, TH hin saistcinga Siler

Genus Rastrites, Barrande.

R. Barrandi, BD in exaidaateistsietaiaietadl a's Nice

Genus Burnoerartus, Hall.

B. laxus, Te. dew swteetretararetattne f ior

Genus Inocautis, Hall.

I. plumulosa, Ts oe ate maajeiayosarsisieiiaell Mave

Genus OxpHamia [?], Forbes. QO. MEULICOSS, Unis, beta tells tesa as wes p

Tt Nova Scotia.

EP bo Slo

a 2i6 .

os lie mn

a o|% 3

> Ts io}

a Iolo . |

fam acl | O | ge | 00/2 . sil esilies Seq olehs & S sf S/£1s ~ =| fo} o|B io] a] ee 5 5 eS Slslslelols slg c |. ao] & o (Q Siroja|s|MolEla 8) ole | S| OD lo es |S) O a2 c\o)/a HIS (0 lZ lO Pp GO| eefeolorlealactes|erlee| Hleeles eolecleetecls | He leelecles eolecleclee| Hleefeslecleeiselee oe . eel Klecles alee . eejyecles efectos eelee eeleelos % i. . ealeslee ee ejee ee ef oe . ae a esleclee se . .| 4 oe eeleew eles soles eoleclee peleelecleeler elecleslecies ele electee eleeleel|selee ol Klee alee eleslecleciee eel Hele elewlee wolecleslee oo| % . eolesleclecien Wiese oe eeleeleuwlealee eelee eleel eofaeleeleasee He leeleelewleefevleclaclerleelec

GRAPTOLITES. 59

§ VIII.—HISTORICAL NOTICE* OF THE GENUS GRAPTOLITHUS.

Folia GRAMINEUM. .-..Bromel. { Linnzeus, Wahlenberg, Beck, Quenstedt, Mur-

GRAPTOLITHUS.++«-- chison, Portlock, De Verneuil, Keyserling, Mather, Vanuxem, Emmons, Barrande, D’Or-

GRAPTOLITES ..2+--- bigny, Geinitz, Suess, Meneghini, McCoy,

Richter, Salter, Nicol, Harkness, Hall.

PRIODON «ee+.ee «.«e- Nilsson.

ORTHOCERATITES....... Wahlenberg, Schlotheim, Quenstedt, Geinitz.

LOMATOCERAS -....+- Bronn, Hichwald.

PRIONOTUS. «24 eeeess- Nilsson, Hisinger.

FUCOIDES--.....05 ...Brongniart, Eaton, Emmons, Conrad.

PETALOLITHUS.-.+.+-- Suess.

Diprion (sub-genus) .. Barrande.

DipymoGRAPTUS ...---McCoy, Salter, and others.

DIPLOGRAPTUS.... +++. McCoy, Salter, Harkness, etc.

Monoprion (s.-gen.) .. Barrande.

MoNOGRAPTUS «...+-- ey Geinitz, Emmons.

CLADOGRAPTUS ..-.- GLOSSOGRAPTUS..... NEMAGRAPTUS,..2+0- | Hmmons. TETRAGRAPTUS.-.... DICHOGRAPTUS .-.... | satter.

A. D. 1727. The graptolites of Sweden were observed by Bromel, who regarded them as leaves of grasses. (Act. Upsal.)

1736. Linneus established the genus Grraptolithus in the first edition of his Systema Nature; and some years later, in the twelfth edition, introduced specific names, (@. scalaris being the type of the genus. This form has been regarded by Wahlenberg, Geinitz, and Barrande as the G. sagittarius, compressed in a direction rectangular to the cellules. The G. sagittarius, Linn., is therefore regarded by the latter author as the veritable historical prototype of the genus Graptolithus and of the family of graptolites. For my own part, I consider the G. scalaris, so far as illustrations of that form have come under my observation, as a distinct type of the graptolite family.

1821. Wahlenberg considered the graptolites of Sweden as very slender orthoceratites. (Nova Acta. Soc. Scien. Upsal, vol. viii, pp. 92 and 93.)

1822. Schlotheim, participating in the opinion of Wahlenberg, described and figured a species under the name Orthoceratites serratus. (Petrefak- enkunde, p. 56, pl. viil, fig. 3.)

* From the earliest notice of the genus Graptolithus to the year 1850, I have added but little to that which has already been published by M. Barrande in his Graptolites of Bohemia.

60 - CANADIAN FOSSILS.

1828. Ad. Brongniart described two species of graptolites from the Transition formation at ‘* Pomte Lévi prés Québec dans le Canada,” as Fucoides dentatus and /. serra.* (Histoire des Végétaux Fossiles, pp. 10 and 71, pl. vi, fig. 7-12.)

1829 [18317]. F. Holl republished the description of Orthoceratites. serratus of Schlothem. (Handbuch die Petrefacten., vol. 1, p. 234.)

18—? Prof. Nilsson recognized the graptolites as polyps belonging to the ceratophydians. He proposed to substitute the pre-occupied name of Priodon for that of Graptolithus. (See Dr. Beck, in Murchison’s Silurian System, p. 696.)

1835. Prof. Bronn, adopting the opinion of Prof. Nilsson regarding the nature of graptolites, gave the name Lomatoceras (Lethea Geognos- tica, vol. i, p. 50, pl. 1, fig. 13, L. priodon), at the same time arranging the species with the orthoceratites, etc.

1857. Hismger described five species of graptolites from the rocks of Sweden, adopting the generic name Prionotus, created by Prof. Nilsson. Among these are two species of Linnzus, P. sagittarius and P. scalaris ; to which he added the new species P. pristis, P. foliwm, and P. convolutus. (Leth. Suecia, p. 118, pl. 85.) In the second supple- ment to that work, published in 1840, two other species are added, under the names P. geminus and P. teretiusculus; the latter being of the type of G. scalaris. (Supp. ui, p. 5, pl. 88.)

1839. Sir Roderick Murchison described and figured in the: Silurian System three species of graptolites, G. Ludensis, G. Murchisoni, and G. foliaceus. (Sil. System, p. 695.)

1840. Prof. Hichwald published a description of Zomatoceras distichus, a graptolite from the Silurian formation of Esthonia. (Stl. Syst. im Esthiand, p. 101.)

1840. Prof. Quenstedt sought to re-establish the opinion that the grap- tolites are true orthoceratites. (WV. Jahrb. f. Min., p. 275.)

1842. Prof. Geinitz described and figured five species of graptolites under the names G. foliaceus, Murchison, G. priodon, Bronn, G. La- densis, Murchison, G. serratus, Schloth., G. scalaris, Linn., and G. spiralis, Geinitz; regarding them as belonging to the Cephalopoda. (NV. Jahrb. f. Min., p. 697.)

1842. Vanuxem identified a graptolite of the Utica slate with the Fucoides dentatus of Brongniart. Graptolithus dentatus, Vanuxem, G. pristis, Hall, His.? (Geol. Rep. 38d Dist. N. Y., p. 57, fig. 2.)

1843. Gen. Portlock, in his Geological Report, discussed the nature

* These species are probably identical with those which I have heretofore described as G. pristiniformis and G. bryonoides.

GRAPTOLITES. 61

of the graptolites, recognizing them as true zoophytes, and indicating their analogy with Sertularia and Plumularia. He suggested that the species may form several genera, belonging perhaps to different orders. The species described and enumerated by this author are indicated under the names G. Sedgwicki, G. distans, G. tenuis, Portlock; G. convolutus, G. sagittarius, G. pristis, and G. folium, Hisiagee: G. scalaris, Linn., G.foliaceus, Lons. (Geol. Rep. on Londonderry, Tyrone, and Fermanagh, pp. 317-321, pls. xix and xx.) The species described by this author as Gorgonia, probably belong to Dictyonema.

1843. W. W. Mather and EH. Emmons recognized Graptolithus dentatus as characterizing the Utica slate. (Geol. Rep. 1st Dist. N. Y., p. 390, and Geol. 2nd Dist. N. Y., p. 279.)

1843. J. Hall described Graptolithus Clintonensis, from the shales of the Clinton group in the Upper Silurian. (Geol. Rep. 4th Dist. NV. Y., p- (2, fig. 12.)

1845. Sir R. I. Murchison, De Verneuil, and Count Keyserling enu- merated G. sagittarius, Hisinger, and G. distichus, Hichwald, as charac- terizing the Silurian formations of Russia. (Geol. of Russia and the Ural Mts., vol. ii, p. 882.)

1846. Prof. Geinitz repeats the opinion expressed by himself in 1842, regarding the nature of the graptolites; and divides them into two sec- tions, the straight and the spiral forms. In the first section he de- scribes four species: 1. G. foliaceus, Murchison, (with which he identifies G. pristis and G. folium, Hisinger, and G. dentatus, Vanuxem); 2. G. priodon, Bronn, (under which he includes G. Ludensis, Murchison, and G. teretiusculus, Hismger); 3. G. sagittarius and G. scalaris, Linn. (which he regards as varieties of the same species), Hwcordes serra, Brong., and G. Murchisoni, Beck; 4. G. serratus, Schlot. (Grundriss der Ver- stein, p. 310, pl. x.)

1846. EH. Emmons published Fucoides simplex [= Graptolithus' seca- linus|, from the roofing-slates of Hoosic. (Natural History of New- York, Agriculture, vol. i, pl. xvii, fig. 1.)

1847. J. Hall described and figured fifteen species of graptolites, mostly new, from the Lower Silurian strata, placing them among zoophytes. (Pal. NV. York, vol. i, p. 265, pls. lxxii, lxxiii, and Ixxiv.)

1848. Rev. Prof. Sedgwick announced the occurrence of Graptolithus sagittarius, His., and G. latus, McCoy, in the Skiddaw slates. (Quarterly Jour. Geol. oe vol. iv, p. 293, )

1848. J. W. aie described G. folium, G. pristis, Hisinger, G. pristis, var. foliaceus, Portlock, G. ramosus, Hall, G. Tenia, Sowerby and Salter, G. tenuis, Portlock, and G. sextans, Hall, from the slates of Loch Ryan, etc. (Quart. Jour. Geol. Soc., vol. v, pp. 15-1T.)

1848. Prof. Philips enumerated the G. Ludensis, G. Murchisoni, and

62 CANADIAN FOSSILS.

three other species in the Builth, Llandeilo, and Haverford-west districts. (Memoirs of the Geol. Survey, vol. ii, part 1, p. 308.)

1849. James Nicol enumerated ant Toshiba Graptolithus Griestonensis, G. convolutus, G. Ludensis, and G. lacus. (Quarterly Jour. Geol. Soc., vol. vi, pp. 63 and 64.)

1849. J. Hall stated the occurrence of twenty species of graptolites in the Lower Silurian rocks; two other species having been found in the Clinton formation.* (Proceedings of the Amer. Assoc. for the Advance- ment of Science, 1849, p. 351.)

1850. J. Barrande published a memoir upon the graptolites of Bohemia, describing seventeen species of Graptolithus, of which fifteen were new 3 anew genus, Rastrites, with four species; and the genus etiolites, with one species. These are all placed among the Polypi. All of these species, except one, are found in the Upper Silurian; four of them occur in the colonies of the inferior division, and pass upward to the superior beds; while one species is restricted to the lower division. M. Barrande has given in this memvir a resumé of the geographical and geological distri- bution of the graptolites in the different countries of the globe.

1850. Prof. McCoy described three species of graptolites, proposing the name Diplograpsus for those with a double series of cellules. He proposed also the generic name Protovirgularia for a zoophyte which he refers to the Gorgoniadx, but which may perhaps belong to the Grap- tolitide. (Annals and Magazine of Nat. Hist., vol. vi, 2nd series, pp. 270-272.)

1850. Prof. Harkness described the graptolites found in the black shales of Dumfries-shire, recognizing two species of Rastrites and ten species of Graptolites. (Quar. Jour. Geol. Soc., vol. vii, pp. 59-65, pl. i.)

1851. Prof. McCoy published descriptions and figures of graptolites from British paleeozoic rocks, adopting the name Diplograpsus for the Species with two ranges of cellules. Of fifteen species which he described, eleven are identified as those of preceding authors, and three of these are recognized as American species. (British Paleozoic Fossils, pp. 3-9, pl. 1 B.)

1851. Dr. H. A. Prout described a graptolite, G. Hallianus [= Den- drograptus|, from the Potsdam sandstone of the St. Croix River. (Am. Journal Science [2], vol. ix, p. 187.)

1851. Edward Suess published descriptions of Bohemian graptolites, reproducing nearly all of those described by Barrande, recognizing several other known species, and describing nine new species. He proposed the name Petalolithus as a substitute for Diprion, = Diplograptus. (Watur-

* This number of twenty species included some forms known, but not at that time described.

GRAPTOLITES. 63

wissenschaftliche Abhandlungen, vierter Band, pp. 88-134, pls. vi, vill, and ix.)

1851. J. W. Salter described G. tenuis, Portlock, and G. bullatus, = G. pristis?, from the Silurian rocks of Scotland. (Murchison, Silurian Rocks of Scotland, Quart. Jour. Geol. Soc., vol. vil, pp. 173 and 174.)

1851. Boeck; Bemarkinger Angaaende Graptolithen Christiania (cited by Geinitz; the work not seen by the writer).

1851. Scharenberg, iéiber Graptolithen (cited by Geinitz; work not seen by the writer).

1852. Prof. Geinitz described the graptolites of Saxony, placing them among zoophytes, and proposing the genera Monograpsus and Cladograpsus for certain forms of graptolites, and the genus Mereograpsus to include Myrianites, Nerettes, ete. He enumerates and describes fifty species of graptolites of his own, or of preceding authors; and one species of Retiolites, R. Geinitzianus. (Die Versteinerungen der Grauwacken-forma- tion, heft 1, Die Graptolithen.)

1852. J.W. Salter described some graptolites from the south of Scotland, recognizing three species. (Quar. Jour. Geol. Soc., vol. vill, pp. 388- 391, pl. xxi.)

1852. J. Hall reproduced the Graptolithus Clintonensis, and described G. venosus, = Retiolites venosus. He also described the genus Dictyo- nema, suggesting its relations with Graptolithus, and likewise the genus Inocaulis. (Paleontology of New-York, vol. ii, pp. 89 and 40, pl. xvii, and pp. 174-176, plates xl F, and xl @.)

1853. J. W. Salter. A new species of graptolite (Didymograptus caduceus, Salter), “from the Lauzon Precipice, Hudson River Group.” (Quarterly Jour. Geol. Soc., vol. ix, p. 87.)

1855. Dr. Emmons described several new species of Graptolites, and proposed the generic names of Wemagrapsus, Glossograpsus, and Stauro- grapsus. (American Geology, vol. i.)

1857. Prof. Meneghini, from collections made by General De la Mar- mora, described ten species of graptolites from the Silurian rocks of the Island of Sardinia, of which eight species were new. (Palcontologie de PLle de Sardaigne.)

1857. J. Hall communicated to Sir William EH. Logan descriptions of twenty-one new species of graptolites from the Lower Silurian rocks of Point Lévis (Lauzon seigniory) near Quebec, (many of the species having compound forms not before known among this family of fossils,) and proposed several new genera. (Report of Progress, Geol. Survey of Canada, 1857. See also the Canadian Naturalist and Geologist, vol. iii.)

1859. J. Hall published Motes upon the genus Graptolithus, with. an enumeration of the Canadian species ; a notice of graptolite-stipes with reproductive cells, together with descriptions of two new species. (Zwelfth Report on the State Cabinet, Albany, pp. 45 and 58, 1859.)

64 CANADIAN FOSSILS.

1859. The preceding notes were reproduced, with descriptions of five additional species of Graptolithus, one Retiograptus, the genus Thamno- graptus with two species, and one species of Rastrites. (Paleontology NV. Y., vol. iti, pp. 495 and 522.)

1860. J. Hall, in continuation of the paper from the Twelfth Report on the State Cabinet (from Paleontology of New-York, vol. iii, Supp.), described additional species of Graptolithus, Retiograptus, Thamnograp- tus, and Rastrites as above. (Thirteenth Report of the State Cabinet, pp. 50-64, 1860.)

1861. J. W. Salter in “ New Fossils from the Skiddaw Slates,” noticed the occurrence of several species of Graptolithus, and the discovery of a branching form similar to those which Sir William H. Logan first brought to light i Canada, which he proposed to term Dichograptus. (Geologist, vol. i, p. 74.)

1861. Prof. McCoy sent to the writer a proof of a plate of graptolites from the ‘‘ Paleontology of Victoria.’ Among the figures are species closely resembling or identical with G. ramosus, G. furcatus, and G. gracilis ; while others resemble G. pristis, G. sagittarius, &c. The descriptions or farther illustrations have not come under our notice.

1861. HE. Billings “ On the occurrence of Graptolites in the base of the Lower Silurian.’ The paper contained a review of the work of Freid- rich Schmidt, and a comparison of the graptolitic zones in Europe and America, with a view to show that the graptolite-schists of Norman’s Kill near Albany are not in the upper part of the Lower Silurian division. (Canadian Naturalist and Geologist, vol. vi, pp. 844 and 548.)

1863. Sir William H. Logan recognized the occurrence of Graptolithus bicornis, G. ramosus, G. mucronatus, and G. pristis, characteristic spe- cies of the shales of Norman’s Kill, in the Utica and Hudson River forma- tions of Canada. (Geology of Canada, p. 200, and Catalogue of Fossils, p- 942. Idem, Graptolites of the Quebec group, pp. 226 and 228.)

1863. J. W. Salter (Note on Skiddaw-Slate Fossils) noticed some new species of graptolites, proposing the new genus Zetragraptus, and describing the genus Dichograptus previcusly proposed and cited above. (Quarterly Journal of the Geological Society, vol. xix, pp. 185-140, with illustrations. )

.*, The Graptolithus from the Hoosic slate-quarries was named by Prof. Eaton Fucotdes secalinus, and the specimens were thus labelled in the cabinet of the Rensselaer School at Albany, as known to the writer from 1832 to 1836; but we have been unable to find any published description.

(Oil is ol cece Nol Olds a iil Ud Uh

J.—SYNOPSIS OF THE SPECIES OF GRAPTOLITIDA OF THE QUEBEC GROUP,

DESCRIBED IN THIS MEMOIR.

A. SPECIES HAVING A BILATERAL ARRANGEMENT OF PARTS. Barrande; Monograptus, Geinitz.)

(Sub-genus Monoprion,

Genus GraPTOLiTHus, Linneeus.

a. Species consisting of two stipes from a single axis.

tus, McCoy ; Cladograptus, Geinitz in part.)

Plate.

(Gio MGS) GGadoodolbonpedooO DOD CoonddoDS ATUL USM are, Cot stat wtatad Shes er dieotatetel alcehetctadet DUT HUSM Herat eatctctetaatetatatcern sce intemetetts ealee HOUTA Prarie evarclcierciciacvelcctetatetetstats et tctahas ATU GL@NGUIS) 2 mial ofieiascicicletatutete tala tatcteictecatetatete ele EXAMS etaters/sersicrcieareleleistetctes ciercisie ree GORTUWAGIES a5 doedtoocodcdoncodosadood

SIMA U Sweretevatareraretarctelcietsls ctor sieeve er elerete ALCU MUS Maletal wine! arelereleietaraiersre/<leisre’iclwisisiel ols EXILES USM velatielintateferepoyaleyaitelsfareterersieretcis/erels PEMA NUIE o6 nonbodobocsoocoSaodudne =

ow DD PH eB eS ee

EWMRHUIOS sosuoocesaoounedoaucsOnade

(Didymograp-

Figure. 1- 9 10-15 16-18 9-10 20 21-22 23-27 1- 5 6-10 11-16 1- 8

6. Species consisting of four simple stipes from a single axis, with or without a central disc. (TZetragraptus, Salter. Dichograptus,

Salter, in part. )

Plate.

GU PU ONGIMes seis aitoisieiels eiaisysisisjeeresieisleeh ic PE YOH Oltbe smerctatertlele's/eis siaicisi= coisa lelalseiere’e OIVOUOIMEREgitecie sc cesrce eer acess wtels Gemticulaseyentstcielslatestclovsievelee cise crete QUITE AGIA DUG wtls:ccc\c'e ds nisi sini ons Qa GTO TA CHA TS alesse cline 's6.0.<:2.0.'s 0'elaials ELUGL COS US) epefeterateyelsidis’sje/sicieleisicic sivic'eeeie © HAULS coodocoucgousocgasudueddat CLUCICI staetatetaietelcietelerereurelaye a stanciere cheers He adit repeveleelatemstefapatcheysielevs totais sie SuoseC'S el VTUSH svetctateved af sievoictefapeliaicrareisis)v aie) eel e/sieye BAGS ily crates eeleleletsfel sisi nialei|sietoisisisieiieieisihO

AvAAMAAHAAD AE HD SP

Figure. 11-12 1-11 a 12-16 1-5

6 6- 8 3

22-30

66 CANADIAN FOSSILS.

ce. Species consisting of eight simple stipes proceeding from a single axis, with or without a central disc. (Dichograptus, Salter, in

part.) Plate. Figure. G. octobrachiatus ...... ah alate stevelaecinye naar (0. nic 1-7 OCLODEACHIADNS ereretelelsistolale’-leies(si0\ ajeia ceva tarevete 1-4 OCtONATIUS. wecceecsceccsssscecens Hoon) ago | 5

d. Species consisting of more than eight simple stipes proceeding from a single axis, with a distinct broad corneous disc. (Dichograptus, Salter, in part.)

Plate. Figure. GAO GANTT ereinte 0101+ «ics wlsieielei=,sivi cle cisleisisniviele 9 eeee 1-9 DUO GAAS WEE leone bnlietes scabs cadniceiceeeRl, senaat t

e. Species with the stipes proceeding from a single axis, and more or less frequently branched during their entire length; not known to have a central disc.

Plate. Figure. (Cp aierallic) o6 cae ago booocdaDOdoS coonbn Gogo) GAsn » See TIPLAMS 1c vice sie veces enss sie neonoscdooaall Maga4 le BPNOLMS ee cine /a/eustere pongoDoce ponocosooodll aesr 6 Richardsoni ..... nisfones stelslereletete tains Sodouc IPA h55 1-8 TAMULUS «0. ceeeeee efalexeternreteratels(ejete eesceelZ coen 9,10

B. Species (so far as known) CONSISTING OF SIMPLE STIPES WHICH ARE CELLULIF- EROUS ON TWO SIDES.

a. Cellules tubular, inclined to the axis, aperture subquadrangular.

Plate. Figure. G. (Diplograptus) pristiniformis......... 13 .... 15-17 oe rhelty nba agin Sysinieicieverarats WSF iajers ee

6. Cellules short and square, aperture transversely-elliptical, appar- ently excavated in the margin of the stipe.

Genus CLIMAcogRapPtus, Hall.

Plate. Figure. — OC PAnteNNATiWs c/s terece cre Aalalee eieletee vee nieins 13 eeee 11-13

Genus Rerioiitss, Barrande.

Plate. Figure. R. GNSILOPMIS Lek vinci aroisierctaels ars lave lola eis. b dia 14 eeee 1-5

GRAPTOLITES. 67

C. SPECIES WITH NUMEROUS SIMPLE STIPES FROM A SINGLE AXIS, IN BILATERAL ARRANGEMENT. (Other species known only as simple stipes.) (Sub-genus Diprion, Barrande; Diplograptus, McCoy.)

Genus RETIOGRAPTUS, Hall.

Plate. Figure. R. tentaculatus eeeereeeoeseeesaseose8e 00080 14 eoese 6-8

D. SIMPLE STIPES WITH QUADRILATERAL ARRANGEMENT OF PARTS.

Genus Puytiograptus, Hall.

Plate. Figure.

Eeatiy PLS matetel siefalel oie el/ajinlelaials\ aha) eheteferelaletstayete LOreis/a/c'ohtoy 11 NCOs oabondeooadoneapoosouGo0HO NS noon EKO) ANNE 55 00 0000 cond dogoonoCoaDdnooDcoDO®) Unoon | IEG ANGUStIfOlIUS weeacecscceeccccceceeseelG «se- LI-21

EK. SPECIES HAVING STEM-LIKE AXES WITH NUMEROUS IRREGULAR RAMIFICATIONS.

Genus Denprograptus, Hall.

Plate. Figure.

PME EUG SSH cveiessicrsiovoyapabenerern miaraielerotatelorevslen Tad weirsie) 012

ALE RCLO SUS! Ai stctaraicielv rene tars cusavereveiersterersraiate eel | rejictey Maa: CINE ERG bob ConU a gOo Bob panodbe coo nciel ilemgcor ars)

SIMI UILS hose roiee never felisveieies fevetolesreialeiwiatsiolerel efor ommlnkiuencfetaye 5 CROCUNS DUOC ROO OOOO CLO ODEO Oe Ione OG 2 Ll mS cna |

EMULE OSS orale slolcteelseie sieleselers eiaisielaren Lite acer | 1y (O569 GHEMCWES, co SgnoouncD NG oe 1 5

LACTIC aelaieieysrelefsyelerelorelsles

eeoeeeoeeve eee eo 18 OOO

eeoeesenrteaoed 18 eecne

F, SPECIES WITH FLABELLATE OR FUNNEL-SHAPED FRONDS, THE BRANCHES OF WHICH ARE CONNECTED BY REGULAR DISSEPIMENTS GIVING A FENESTRATE STRUC- TURE, OR BY UNFREQUENT AND IRREGULAR TRANSVERSE BARS, AND SOME- TIMES BY AN ANASTOMOSING OF THE ADJACENT PARTS OF THE BRANCHES.

Genus CaLLoeraptus, Hall.

Plate. Figure. OSele oan aiiatratatatera acces olsjale sicwalaaleteiaars 19 eooo 1-4 Saliterimmyyverteyterctsiciecesaavs avercveudiareunerees 19 eoee 5-8

Genus Dicryonema, Hall. (Grapropora, Salter.)

Plate. Figure.

PD) Innes ular iseyreatlaeiieeiens =< sisie\aretemeinicis U2 Oi seit, lolooe HOWE, ooootodgsoudoboocodsdGdounED ZO) “cea5) Be QuadrangUlarigncsiaccvecsccs erences 20

eeoeseo 5 Murrey. jtelattatetsteistare iaiets shatayateleraiel selo/cteho 6

68 CANADIAN FOSSILS.

G. SPECIES CONSISTING OF BRANCHES WITH SUB-CYLINDRICAL OR ROUNDED AXES; THE ULTIMATE PINNULA ELONGATE, SETIFORM, OR PLUMOSE, AND ALTERNATELY ARRANGED ON THE TWO SIDES OF THE AXIS OR LARGER RAMUS.

Genus Prinoeraptus, Hall.

Plate. Figure. up UMYOS US terrae veraretonelclataltstelals sielelo\(ela/slele/a/elelelera ntl ametatets 1-4 GIMitZ anise peveror siete ayaa) oveia.'s wie: e.ete.e ece/everevelere 21 econo 5-8

Genus THAMNOGRAPTUS, Hall.

SPECIES INTRODUCED FROM THE UTICA SLATE OF LAKE ST. JOHN, FOR COMPARISON AND ILLUSTRATION.

GRAPTOLITHUS. Plate: Figure. G. (= Monoprion = Didymograptus) flaccidus..... 2 .... 17-19 G. (= Diplograptus) quadrimucronatus...... Gonos opoa ae RETIOGRAPTUS. Plate. Figure. Retiopraptos CuCharis js,s,e0c0ce ee pra aciele seus sce'ee) LAT) tle nls 9

§ I[.—DESCRIPTIONS OF THE SPECIES OF GRAPTOLITIDH FIGURED IN THIS MEMOIR.

Genus GRAPTOLITHUS, Linneus.

Generic Characters.—Polypidom or frond consisting of slender elongated stipes or stems, which are flattened and quadrangular, and may be simple or compound, and sometimes bifurcating. The cellules take their origin from a common body or canal, which is parallel to a slender axis.

Some of the species have the cellules in single series, and others have them in two series, arranged on opposite sides of the stipe.

Those species with the single series of cellules (Monoprion, = Mono- graptus) have the axis marginal; while those with the two series of cellules (Diprion, = Diplograptus) have each series entirely independant of the other and separated by a double solid axis, leaving no communi-

GRAPTOLITES. 69

cation between the series, each of which has its common body or canal, as in those with the single series of cellules. This character is clearly shown in some of the bi-celluliferous species, which subdivide above the base by the dehiscence of the axes.

The species having a single series of cellules are developed in a bilateral arrangement of the parts on the two sides of a central point or radicle. The simplest forms known consist of two single elongate stipes ; others have four, eight, or more simple stipes ; while in other species the stipes are variously bifurcated ; but in all they are symmetrically and bilaterally arranged upon the two sides of the specimen. Many of these compound forms have the bases of the stipes united in a central corneous dise or cup, which is of the same substance as the stipes, thickened in the middle, and attenuate at the margins, and which in the living condition was probably of a concayo-convex form.

The centre of these dises on the exterior side often presents a small prominence or point, which however does not bear evidence of having been attached, at least during the later periods of the animal’s life.

The species under this genus may for convenience be distributed in two sections with several subordinate divisions, as shown on pp. 65 and 66.

1. GRAPTOLITHUS NITIDUS, Hall. Plate I, figures 1-9. (G. nitipus, Hall: Geological Survey of Canada, Report for 1857, page 129.)

Description.—Frond composed of two simple stipes proceeding from a small radicle, and diverging at an angle of about 175°. Stipes narrower at the base, and gradually widening towards the extremities, which in perfect specimens are somewhat rounded from the partial development of two or three of the terminal cellules. Radicle short, abruptly tapering to a slender point. The stipes in their greatest width are from six to ten hundredths of an inch, while near the base they are often not more than five hundredths of an inch in, width. The proportion of the stipe occupied by the common body is about one sixth, or less than one sixth of the entire width. In the broader stipes, the limits marked by the pustuliform elevations indicate the bases of the cellules. In some spect- mens, one fourth of the width is occupied by the common body.

Cellules long and narrow, from thirty-two to thirty-four in the space of an inch, curving slightly upwards, nearly twice as large at the

E

70 CANADIAN FOSSILS.

aperture as at the base, and about three times as long as their greatest width when the stipe is flattened ; inclined to the axis at an angle of from 35° to 45° ; division-walls of cellules in contact, or united for three fourths of their entire length ; margin of the aperture straight, or slightly curved near the anterior edge, making an angle of 110° or 112° with the axis ; the anterior » margin, in the broader stipes, lies over the base of the third cellule in advance. The limits of the cellules are strongly marked by a line imdi- cating the place of the partition or divisional cell-wall, which on one side often terminates below in a pustule.

This beautiful little species differs very distinctly from all others of the genus which I have studied; and it bears little relation to any of the European forms described, so far as they have come under my observa- tion. The substance of the stipe is usually thickened, brownish-black in color, smooth or slightly wrinkled from desiccation, and rarely marked with distinct striz parallel to the cell-margins. The strize apparently indicate the successive stages of growth or development of the cell-walls. The divisions between the cellules are strongly marked by what usually appears to be a distinct groove produced by the folding of one cell over the other at the lme of junction, this line indicating the place of the cell-partition. The sheath or common body of this species is usually partially filled with stony matter, and a section presents an extremely elongated oval form. This condition may be partly due to the original character of the body, or to the nature of the matrix; which is less finely lammated than some of the graptolitic slates, but preserves the fossil in a very beau- tiful manner. The imprints are stamed by oxide of iron, and the striz marking the divisions of the cellules are often well preserved. The trans- verse strize parallel to the apertures of the cells are often distinctly seen in casts of the interior.

The minute tubercles marking one side of the stipe are rarely shown on the two sides, and sometimes on neither side. ‘The conditions of pressure may have had some influence in causing this appearance ; since the pomt of the abrupt bending of the partition between the two cellules may have resisted more than the other parts, and thus produced the promimence observed. The proportions of parts are subject to slight variations, dependent mainly on the degree of stipe-development. In the narrower forms, the-cell-aperture often lies vertically above the base of the second cellule in advance,,instead of above that of the third as in the wider forms. In the relations of the cellules to each other, they appear . as if the pressure had been exerted obliquely to the direction of the axis; the cellules being slightly en échélon. 'There are however many indica- tions pointing to such an arrangement as being the original disposition of the cellules on the axis, not only in this but in other species.

The impressions of G. bryonoides resemble those of this species; but

GRAPTOLITES. 71

the stipes are broader, the striz less rigid and distinct, and the tubercles and coarser denticles of G. nitidus are absent. In mode of growth and general aspect, this species resembles G. serratulus of the Hudson River group (Pal. N. Y., vol. 1, p. 274, pl. Ixxiv, fig. 5 a, 6); but in the latter the denticles are coarser and more oblique, the lower side bemg much the longer, and the stipes are more distinctly lmear; while in G. nitidus the stipes become gradually wider from the base, and are very distinctly striate and pustulose in well-preserved specimens.

EXPLANATIONS oF FiguRES OF GRAPTOLITHUS NiITIDUS, Hall. Puate I.

1. A young individual preserving the radicle and the two stipes.

2. The extremity of a stipe enlarged, showing the partially-developed cellules.

3. A larger specimen of similar character to fig. 1, showing the pustules at the base of the cellules. The extremities are not quite entire.

4. A part of the left side of fig. 3 enlarged, showing the pustuliform elevations.

5. An enlargement from another specimen, with the cellules obliquely compressed, and the pustules obscurely shown.

6. Two smaller individuals, which, from juxtaposition, similarity of size, etc., seem as if they may have originated from a common base.

7. An impression of a more extended form, which is proportionally narrower than fig. 3.

8. A still narrower form of stipe, diverging almost rectangularly from the direc- tion of the radicle.

9. A well-preserved small individual, enlarged three diameters.

Formation and Locality.—Shales of the Quebec group; Point Lévis.

2. GRAPTOLITHUS PATULUS, Hall.

Plate I, figures 10-15. (G. patuLus, Hall: Geological Survey of Canada, Report for 1857, page 131.)

Description.—Frond composed of two simple stipes diverging almost rectangularly from a small radicle. Stipes long, linear, widening very gradually from the base to the extremities, which are somewhat rounded from the immaturity of the later cellules. Width from base of serratures to the back of the stipe, from one sixteenth to one twelfth of an inch. Surface strongly striate in the direction of the cellules; strize curving. Radicle minute. The proportion of the stipe occupied by the common body varies from a perceptible line to one fifth of the entire width, and is dependent partly or entirely on the direction of the pressure.

72 CANADIAN FOSSILS.

Cellules distinctly limited by the partition-walls, about from twenty-four to twenty-six in the space of an inch ; rather wide, making an angle of about 60° with the direction of the axis, and slightly curving upwards; their pro- portions vary according to the width of the stipe, bemg from three to four times as long as wide. Outline of the aperture curved, concave, making an angle with the axis of about 130°; on the lower or posterior side produced into mucronate points which curve gently forward: walls of the cellules distinctly striated parallel to their margins, for one half the depth. The anterior margin of each cellule is vertically above the base of the second cellule in advance.

Fragments of this species are numerous upon some slabs of greenish or blackish-green slate where other species occur. ‘The remains of single stipes are sometimes four or five inches in length, showing in different individuals little variation in width after becoming perfectly developed, which occurs within an inch of the radicle. Sometimes the stipes are compressed vertically, and present the smooth limear base or exterior, which is less in width than when compressed laterally. The lateral faces of the stipes exhibit some variety of surface, dependent on the degree of compression, or in some instances, on the replacement or filling of the inte- rior by iron pyrites. In these cases, or when the branch is not flattened, the surface is deeply striated or wrinkled obliquely. Sometimes when extremely compressed, the surface has an appearance of vesicular struc- ture, which is probably due to influences attending the mineralization of the fossil, or the fillmg up of the original canal.

This species is palpably different from the last in the greater extent of the stipes, and in their almost perfectly linear character. The form of the denticles, and their angle with the axis, as well as their proportional dis- tance, are distinctive characters. The G. virgulatus of Beck (Geinitz’s Graptolithen, page 387, pl. v, fig. 86) bears some resemblance to this species in the figure of natural size; but our species does not correspond with the enlarged figures.

EXPLANATIONS OF FiguRES OF GRAPTOLITHUS PATULUS, Hall. Puate I,

10. A specimen preserving the radicle, and a stipe on one side two and a half inches in length.

11. The distal extremity of a larger stipe. Some of the cells are filled with iron pyrites.

12. A short stipe broken off near the radicle, showing the narrow form near the base, and a greater width beyond, exceeding that of the ordinary forms.

13. A part of fig. 12 enlarged.

14. A part still further enlarged to show the striz parallel to the cell- -apertures.

15. An enlargement from fig. 11, where some cells are filled with iron pyrites, showing their extension almost to the back of the stipe.

GRAPTOLITES. 73

Formation and Locality.—Shales of the Quebec group; from loose masses below the village of Point Lévis.

8. GRAPTOLITHUS BIFIDUS, Hall. (un. s.)

Plate I, figures 16-18 ; Plate III, figures 9, 10.

Description.—Frond two-stiped: stipes diverging from the small short radicle, and curving slightly imward, and thence extending in right lines including an angle of from 15° to 20°, varied by growth or accident. Stipes very narrow, rounded at the base, and gradually expanding above, attain- ing their greatest width at about two thirds of the distance from the base, from which they are gradually narrowed to the extremity; they curve on the celluliferous margin, and are essentially straight on the back. The cellules continuing to increase in length as the stipe is extended to the pomt of greatest width, give the peculiar curving outline to the celluliferous margin. In the stipes of ordinary width, about one sixth of the space is occupied by the common body ; though this proportion varies with the development of the stipe. Test thin, nearly smooth, or with faint striz parallel to the cell-margins: divisions between the cellules strongly marked, and frequently termimating below in a minute pustule. The width of stipe varies from one fifteenth of an inch at the base, to one eighth or even one fourth of an inch in the widest portions. Cellules long and slender, except afew at the base, and some partially developed near the apex: the length of the cellules is from three to four and a half times their width, according to the degree of develop- ment, and they incline to the axis at an angle of 48° near the lower part, curving more directly upwards in the middle, or more fully developed part of the stipe. Near the base of the stipe the angle of the cellules is greater, and towards the apex it is less, until the last few are inclined at a very low angle. The cellules are free for from one fourth to one third of their length. The apex is extended in a sub-mucronate point. The curving of the cell- margin forms an angle of about 120° with the axis in the widest part of well- developed stipes.

This species is very peculiar, differing from all others described in this memoir (except G. pennatulus) in the great inequality of width in the stipe, and the apparently continuous increase of width from the extension of the cellules; while the younger cellules near the apex seem to be slowly developed. The stipe at the base is nearly round. Of the earlier cellules usually four or five and sometimes six or seven do not attain

74 CANADIAN FOSSILS.

the full proportions. In several specimens (and indeed in all those upon which the species was originally founded), the stipes diverge from the radicle at an angle of 15° or 20° with the celluliferous faces on the inner or approximate margins. A later examination of other collections shows some specimens where the divergence is greater, and the development of parts more excessive.

Three individuals of this species from the shales at Point Lévis preserve very constant characters in the mode of growth and structural details. One, a single stipe much longer than the others from the same locality, pre- sents some departure from the prevailing characters, and is referred with hesitation to this species. Another specimen among later collections from above the river St. Anne, has more divergent stipes and a stronger form than those first described. In the imperfect condition of preservation of these specimens, it is not easy to determine what extent of variation in individuals of this form may be due to the mode of growth and to other causes.

EXPLANATIONS OF FiGURES OF GRAPTOLITHUS BIFIDUS, Hall. Puate I.

6. A small specimen from the same fragment of slate with fig. 17. 17. An individual of ordinary size. 8. An enlargement of the upper part of one stipe of fig. 17.

Puate III. 9. An individual of this species, having a greater divergence of the stipes than is usually observed.

10. An enlargement from one of the stipes of the preceding, showing the form of serratures, and the minute pustules at the base of the cell-divisions.

Formation and Localities.—Shales of the Quebec group ; Point Lévis, and three miles above the river St. Anne.

4, GRAPTOLITHUS INDENTUS, Hall.

Plate I, figure 20.

(GRAPTOLITHUS INDENTUS, Hall: Geological Survey of Canada, Report for 1857, page 128.)

Description.—Frond consisting of two simple stipes, diverging at the base from a slender radicle, and making an angle between the two of 50° for the first quarter of an inch, and above this continuing in a nearly par-

GRAPTOLITES. ‘ 75

allel direction. Test somewhat rough : width of stipe about six hundredths of an inch; the back marked by a strong axis, and a scarcely appreciable portion occupied by the common body. Cellules narrow, distant, about twenty in the space of an mch; each one having a length of about three times its width, half of the length being free ; inclined at an angle of. about 35° to the axis: aperture at right angles to the axis; the apex acute and pointed.

This species bears a resemblance to G. extenwatus in the width of stipe and proportional distance of cellules; but the angle of inclmation of the cellules and the form of aperture are quite different ; the absence of pustules at the base of the cell-divisions is also a very distinctive character. The stipes of this species bear a very close resemblance to those of G. quadribrachiatus ; but the individual figured, in which the base is pre- served, shows in its peculiar curving and smaller serratures near the base, a feature which belongs only to the two-stiped forms. The cellules also appear to be narrower, and are slightly closer in their arrangement ; stipes of the same size of the two species, showing respectively eighteen and twenty cellules in equal spaces.

EXPLANATION or Ficure or GRAPTOLITHUS INDENTUS, Hall. Puate I.

20. An individual of the natural size, the continuation of the stipes having been broken off.

Formation and Locality.—Shales of the Quebec group; Pomt Lévis.

}. GRAPTOLITHUS EXTENUATUS, Hall. (n. s.) Plate I, figures 21, 22.

Description. —Stipe slender, linear, straight ; substance smooth, except the striz mdicating the cell-partitions ; width a little less than one twentieth of an mch, the common body occupying a little more than one quarter of the width. The back of the stipe is marked by a strong marginal axis. Radicle unknown.

Cellules narrow, very gradually expanding from the base, length about three and a half times the width ; making an angle with the axis of nearly 20°, and curved near the base. Apertures truncate, slightly curved to- wards the anterior margin, and nearly at right angles with the axis; free

for about two fifths of their length ; about twenty-four in the space of an

76 CANADIAN FOSSILS.

inch. The apex of the cell-denticle or aperture is a little forward of the tubercle marking the base of the second cell in advance. ‘The cell- partitions or septa are not strongly marked, but distinct under a lens, and terminate below in a minute rounded process or pustule.

(The specimen on which this description is founded is a fragment of two and a half inches long. Other fragments on the same piece of weathered shale appear to be identical with it, but are too obscure for satisfactory determination. It is supposed to be a bibrachiate form.)

This species bears considerable resemblance to the figure of G. tenuis of Portlock, as given by McCoy (Brit. Paleozoic Fossils, pl.i. B, fig. 4 a, b); but the stipe of that one shows no pustule at the base of the cell-division. The original figures of Portlock do not however correspond so nearly with our species in its cellules, while the axis is not so strongly developed. Compared with any of the Canadian forms, except G. extensus, it is proportionally narrower ; with that one it corresponds in the number of serratures in the same space ; but the angle made by the cellules with the axis is very different, and the presence of pustules is a distinguishing feature. From all other analogous forms, this one varies in the form, proportional number, and inclination of the cellules.

EXPLANATIONS OF Figures oF GRAPTOLITHUS EXTENUATUS, Hall.

Prats I,

21. A fragment of the stipe, natural size. 22. A portion of the lower extremity enlarged ; a part of the specimen retaining the substance of the fossil, and a part being an impression in the slate.

Formation and Locality.—Shales of the Quebec group; Point Lévis.

6. GRAPTOLITHUS consTRIcTUS, Hall. (n. s.) Plate I, figures 23-27.

Description—Frond composed of two slender stipes, which diverge almost rectangularly from a minute radicle, or are usually bent a little back- wards, a feature which is more conspicuous in young individuals. The stipes attain their full dimensions near the radicle, maintaining nearly an equal width throughout their length : the extremities are somewhat rounded from the partial development of some of the terminal cellules. The stipes in their greatest width are about nine hundredths of an inch, and vary

GRAPTOLITES. vi

from five to nine hundredths in their different stages of growth and devel- opment. .The common body occupies a very small proportion of the entire width, and its limits are not distinctly defined. Surface of stipes quite smooth ; test very thin, and cell-walls usually obscurely marked.

Cellules of moderate length, from twenty-four to twenty-six m the space of an inch, and inclined to the axis at an angle of about 32°, as indicated by the lines of the cell-partitions : line of the aperture truncate, or very slightly convex, making an angle of 120° with the axis, and nearly rectangular to the direction of the cellule. The cellules, in their lower part, and for two thirds of their length, are straight, and scarcely wider throughout than at their origin: at this point, just before becoming free, they are abruptly expanded on the posterior side, and this margin of the free extremity makes a larger angle with the direction of the axis. This expansion of the cellule is perhaps as properly a sudden constric- tion just below the orifice, or at the base of the cell-denticle. The cell- denticles, under a strong lens, are seen to be finely striated parallel to the line of the aperture.

This species in its mode of growth and general form resembles G. patulus, but in its development it earlier attains the full width of the stipe. It is always smoother on the exterior surface, and the cell-walls rarely make distinct strize, as in that species, though this character is visible under a lens. The form of the denticles is however very characteristic; and this at once distinguishes it not only from G. patulus, but also from every other species of this group. It is associated in the same slates with G. patulus and G. quadribrachiatus.

A specimen in the shales of Gros Maule, preserving all the essential features of this species, has apparently a thicker test, and the interior is partially filled with stony matter, so that the parts are more clearly seen. In this one the cells show a very gradual expansion towards the aperture, and a slight curvature of the cell-partitions near the base, while the con- striction below the cell-mouths is more strongly pronounced.

EXPLANATIONS oF Figures or GRAPTOLITHUS consTRICTUS, Hall. PuateE I.

23. A young individual of the natural size.

24, An older specimen.

25. A part of a much more extended stipe, but which is not wider than fig. 23.

26. A part of a stipe from Gros Maule.

27. An enlargement showing the form of cells, the cell-denticles or apertures, and the characteristic apparent constriction. '

Formation and Localities.—Shales of the Quebec group; from some loose masses below the village of Point Lévis, and from Gros Maule.

78 CANADIAN FOSSILS.

7. GRAPTOLITHUS SIMILIS, Hall. (n. s.) Plate II, figures 1-5.

Description.—Frond consisting of two narrow sublinear elongate stipes, proceeding from a small pointed radicle, from which they diverge almost rectangularly : stipe acquiring its full width near the radicle, having a short space near the base without cellules ; extremities somewhat rounded, from the partial development of the cellules. The stipe varies from five to ten hundredths of an inch in width: the cell-partitions, when visible, extend nearly to the back of the stipe, leaving a narrow space occupied by the common body. Surface nearly smooth : cell-partitions seldom seen, and not distinetly visible ; the specimens extremely compressed.

Cellules somewhat short and broad, little curved, about twenty-one in the space of an inch, inclined at an angle of 23° to the axis. The cellules are from two to three times longer than wide, this depending on the width of stipe: margin of aperture truncate, making an angle with the axis of from 118° to 180°; the cell-walls show obscure striae parallel to the aperture. The apex of the denticle is vertically above the posterior basal edge of the second cellule in advance.

The nearest affinities of this with any American species are with those designated by me as G. sagittarius and G'. serratulus from the shales at Norman’s Kill, near Albany ; but the cellules make a much less angle with the axis of the stipe, and the whole body is less robust than the larger specimens of Gt. sagittarius. It bears a remote resemblance to the figures of G. nuntius of Barrande, as given both by Barrande and Geimitz; approaching more nearly to the figures of G. sagittarius of Hisinger, as given by Geinitz, than to any of the others; though these figures give a higher angle between the axis and the direction of the cellules. The angle made by the cellules of: G. nuntius with the axis, as given by Barrande, is 45°, which corresponds with our Norman’s Kill specimens ; but they differ in other respects. The present species differs from most of the other Canadian species in the straightness of its stipe ; and in the low angle made by the cellules, from all others, except G. indentus.

The specimens are replaced by pyrites in a dark or nearly black slate, and associated with other forms too imperfect to be identified ; one of them resembling G. guadribrachiatus, and another G. bryonoides.

GRAPTOLITES. 79

EXPLANATIONS oF Figures OF GRAPTOLITHUS sIMILIs, Hall.

Puate II.

1. A very young individual of this species.

2. An individual somewhat more matured. 3, An enlargement showing the form of the radicle, and the cells near their origin,

with a non-celluliferous space between. 4. A fragment of a longer stipe, which is imperfect at both extremities.

5. An enlargement of fig. 4.

Formation and Locality —Shales of the Quebec group; three miles above the river St. Anne.

8, GRAPTOLITHUS ARCUATUS, Hall. (n. s.) Plate II, figures 6-10.

Description —Frond consisting of two simple widely divergent stipes proceeding from a small radicle, and bent backwards or downwards, mak- ing on the upper side nearly or more than a right angle with the direction of this radicle, and then curved gently upwards; presenting a broadly arcuate stipe gradually expanding in width from the base to the extremity, and celluliferous throughout its entire length. A single denticle, or similar process, appears above the rootlet. Radicle short, obtusely pointed. The stipe is from four to ten hundredths of an inch in width. The cellules reach nearly to the back of the stipe, leaving a narrow space to be occupied by the common body. ‘Test extremely compressed in the specimens examined, and towards the extremity of the cellules almost transparent. The whole has a white or silvery lustre (probably due to iron pyrites), and no lines or striz are visible except those marking the separation of the cellules.

Cellules narrow and very little expanded towards the aperture, about twenty in the space of an inch, slightly curving upwards, and inclined to the axis at an angle of about 30°, varying a little with the curvature and development of the stipe ; from three and a half to four times as long as broad. Cell-apertures slightly curved, nearly vertical towards the poste- rior side and arching towards the anterior side. The apex of the denticle, or posterior side of the aperture, is vertically above the base of the third cellule in advance of it.

In some specimens the radicle is broken off, and there is a process on the opposite side, giving the appearance of a radicle on the celluliferous

80 CANADIAN FOSSILS.

side of the specimen, as if the cellules had been turned downwards ; but } this appearance is fallacious. In examples where the radicle is broken from the margin of the stipe, the question is suggested whether it may have been a quadribrachiate species; but the pointed radicle in others is opposed to the supposition. In the specimens from which this description is drawn, there are several examples of two individuals lying with the celluliferous margins nearly or quite in juxtaposition ; while the stipes crossing each other at a distant point may give an erroneous impression regarding their mode of growth.

On a cursory examination of the specimens before us, this species is readily identified by the peculiar curving of the stipes; differing in this respect from all the bibrachiate forms which have been observed. In the form of the denticles, or free portions of the cellules, this species approaches G. patulus ; but these parts are less mucronate, and the angle between the axis and the cellules in that species is much greater, and the cellules are narrower. The general form of stipe, except in its peculiar curvature, does not differ essentially from some others previously described ; but a comparison of the form of the cellules, their proportionate dimensions, and angle of inclination, will suffice to show its distinctive character.

EXPLANATIONS OF FiguRES OF GRAPTOLITHUS ARCUATUS, Hall. Puate II.

6. A stipe of a small individual, more than usually curved.

7. A stipe having a process just above and opposite the radicle.

8. A larger stipe, the cellules very clearly preserved.

9. A specimen showing the stipes on both sides of the radicle, and preserving their peculiar curvature very perfectly.

10. An enlargement of a portion of one of the stipes.

Formation and Locality.—Shales of the Quebec group ; Point Lévis.

9. GRAPTOLITHUS EXTENSUS, Hall.

Plate II, figures 11-16. (G. extensus, Hall: Geological Survey of Canada, Report for 1857, page 132.)

Description.—Frond consisting of two simple linear very slender stipes, which diverge at right angles to the direction of the minute radicle, and lie in the same plane. Stipe near the radicle one fiftieth of an inch in diameter, and at a distance of four inches from the radicle, one tenth of

GRAPTOLITES. 81

an inch in diameter. Fragments of single stipes have been observed, having a length of six or seven inches, with a width not exceeding that given above. Surface usually smooth; the strize formed by the cell-partitions sometimes visible ; the back of the stipe somewhat thickened, and about one fourth of the width occupied by the common body.

Cellules short and comparatively broad, very slightly curved ; about twenty-four in the space of an inch, and making with the axis an angle of about 40°. Margins of the aperture truncate, making an angle of 98° with the axis: one third or more of the cellule is free; and near the radicle, one half of the length of the cellule is free. The partitions are distinctly visible in well-preserved specimens; but in most instances they are obscure.

In this collection, the specimens are mostly upon weathered surfaces of the slate ; the substance is often partially removed, and no good impressions are preserved. This species is most nearly allied to G. s¢mzlzs, but is always more slender near the base: the serratures are more distinct in smaller stipes, and the angle of the cellules with the axis is much greater ; while the angle formed by the cell-aperture with the axis is much less than in that one. Ji differs equally from the allied Kuropean forms, in some respects approaching the G. sagittarius as represented by Geinitz (Graptolithen, -ete., pl. u, fig. 4); but it has more the aspect of G. Wilssoni (fig. 17 of same plate). It differs essentially however from G. WVilssoni as repre- sented by Barrande (Graptolites de Bohéme, pl. 1, figs. 16 and 17), and from the figs. 19 and 31 of Geinitz, which our species never approaches in any stage of growth. In our specimens we see the con- nexion of the stipes with the radicle, and trace them continuously for four or five inches; and in separated fragments, we have specimens six or seven inches long. None of these offer an approximation in variations of form and proportional distance of cellules, to those represented by Geinitz as different phases of G. Milssont. We may add, that if such differences exist in the same species, we have then no means of fixing the limits of specific variation, or of determining the species among graptolites of this character, from the separated fragments. The comparatively large number of specimens in the Canadian collection affords good means of specific deter- mination for many of the forms; and unless we could find upon the same stipe, evidences of such variation, we should hesitate to consider the different varieties as one species.

The G. Nilssont, as figured by Harkness (Quart. Jour. Geol. Soc., vol. . vil, p. 62, pl. i), differs from our species, and more nearly resembles the

figures of Barrande. a

82 CANADIAN FOSSILS.

EXPLANATIONS OF Figures or GRAPTOLITHUS EXTENSUS, Hall. Puate II.

11. A single stipe more than four inches long, with the radicle and part of the

opposite stipe. 12. A fragment showing a part of the stipe on each side of the radicle, natural size. 13. The radicle and adjacent cellules, enlarged from fig. 12. 14. An enlargement of fig. 12 at a point about two inches from the radicle. 15. A fragment of a stipe where the cellules are distended by iron pyTiies: This fragment may belong to a different species. 16. An enlargement from fig. 15.

Formation and Locality.—Shales of the Quebec group ; Point Lévis.

10. GRAPTOLITHUS PENNATULUS, Hall. (a. s.) Plate III, figures 1-8 ; and Plate V, figure 9.

Description—Frond consisting of two stipes, which diverge rectangu- larly, or are more or less ascending from a small radicle. Stipes narrow at the base, gradually or rapidly increasing in width for about two thirds of their length. At the base they measure not more than three or four hun- dredths of an inch, and increase to one tenth of an inch in the narrower indi- viduals ; while the widest observed is three tenths of an inch at one third of the length from the base, beyond which point it is somewhat narrower. They are all more or less contracted towards the distal extremity, curved on the celluliferous side, and nearly straight on the back: the terminal cellules are developed in a line nearly parallel with the axis. The proportion of the stipe occupied by the common body is from one seventh to one fourth of the entire width. The test is apparently smooth ; that of the back of the stipe and partitions of the cells seems to be considerably thicker than the outer walls of the cellules.

The cellules, when fully developed, are long, narrow, and curved up- wards, making an angle with the axis of from 30° to 45° im different indi- viduals at the base of the cellules, and as high as 70° on the outer part of some of them; while the average angle, taking a line from the base to the point of the cellule, is from 50° to 57°. The line of the aperture is curved : the pellicle forming the cell-walls extends along the posterior side of the cell- partition next in advance, the line of aperture making an angle with the axis of from 110° to 120°; while the extremity of the denticle is mucronate. ‘The fully-developed cellules have a length of eight times

GRAPTOLITES. 83

- their width; and in the narrower stipes, the length of the cellule is about five times the width. There are from twenty-four to thirty-two cellules in the space of an inch: (the specimen having thirty-two in an inch is a young individual, in which the cellules are more crowded, and not fully developed.) The apex of the denticle is vertically above the base of the fourth or fifth cellule in advance, varying in the narrower stipes to the third cellule in advance.

This species differs from all the others described, except G@. bifidus ; and this it very much resembles in the young individuals. There is an absence of pustules at the base of the cell-partitions, with a greater thick- ening of these partitions, and the denticles are usually more mucronate. If uniformity im the divergence of the stipes can be relied upon, this char- acter will aid in distinguishing the species ; but this feature may vary from accident, as In one specimen figured, which appears to have been broken in one of the stipes. This species is remarkable for the great development in the width of the stipes, which, in their extremely compressed condition, have the appearance of feathers mbedded in the shale.

The specimens from which these figures have been drawn, present the fossil in a very unsatisfactory condition; and farther collections may show the necessity of separating some of the narrower forms under another specific designation.

EXPLANATIONS OF Figures oF GRAPTOLITHUS PENNATULUS, Hall. Puate III.

1, A young specimen with the minute radicle, the stipes diverging almost horizon- tally, or rectangularly to the radicle.

2, A young specimen with one stipe entire, and a part of the other, less divergent than fig. 1.

3. A single imperfect stipe of a young or half-grown individual, which is narrower than usual.

4. A larger stipe, which is entire from the base to the apex.

5. A large or full-grown single stipe, which is nearly entire.

6. An enlargement to three diameters from fig. 4, showing the form and proportion of the cellules, and cell-denticles.

7. An enlargement to the same degree as the preceding, from fig. 5.

8. A young specimen where the stipes are twisted near the base, giving an appearance as if the serrations were on the outer or lower side in relation to the direction of the radicle.

PLate V.

9. A single stipe of this species? The specimen is a large stipe, somewhat obscurely preserved upon the surface of a slab of slate, with G. extensus, G. bryun- oides, and Phyllograptus ilicifolius. It is from the same locality with G. bifidus at Point Lévis. In the form of the stipe, and its gradual diminu- tion towards the distal extremity, as well as in the absence of visible pus- tules at the base of the cellules, it has the habit of G. pennatulus. Being the only individual observed from this locality, and the resemblance to

G. bifidus being very close, I haye referred it with much hesitation to G. pennatulus.

84 CANADIAN FOSSILS.

Formation and Localities—Shales of the Quebec group ; three miles above river St. Anne, and at Pomt Lévis.

11. GRAPTOLITHUS BRYONOIDES,* Hall. Plate IV, figures 1-11; Pl. III, figs. 11, 12 (2); Pl. VI, fig. 4 (?).

(G. srronorpss, Hall: Geological Survey of Canada, Report for 1857, page 126. Fucoides serra, Brongniart, Végétaux Fossiles, vol. i, page 71, 1828.)

Description.—Frond consisting of four simple stipes, united in pairs at their bases, and connected by a short funicle of variable length, from the centre of which proceeds a minute pointed radicle. The stipes diverge at various angles (dependent probably on distortion from pressure) ; narrow at their origin, and abruptly expanding above, they acquire their full width within the distance of three or four cellules, and maintain the same through- out their length to near the distal extremity, which is somewhat abruptly rounded and occupied by the partially-developed cellules. The full width of the stipes in young individuals is often not more than one twelfth of an inch, and in mature specimens about one seventh of an inch; the base having a diameter of not more than two or three hundredths of an inch. The common body occupies avery narrow space, and the solid axis is strongly defined in the flattened specimens. The substance of the stipe or pellicle is quite thin and apparently smooth, the only markings visible being the oblique strize made by the cell-partitions.

Cellules elongate, of medium width, somewhat curved, and in the fully- developed condition about four times as long as wide, making an angle of from 40° to 50° with the axis; free for about one fourth of their length ; about from twenty to twenty-four in the space of an inch, varying in differ- ent individuals and in different stages of growth. Aperture curved, making an angle of about 110° with the axis; the cell-denticles pointed,

* T have little doubt that this species is identical with Fucoides serra of Brongniart (Vég. Fossiles, p..70, 1828). The locality of that species is “‘ Pointe Levi prés Quebec,” which is the same with that of G. bryonoides: and the figures of Brongniart correspond with figs. 9 and 10 of plate 4 of this memoir. The Fucotdes dentatus of the same author is also probably identical with G. pristiniformis of this memoir, being from the same locality. It is only since these descriptions have been in print, and published references made to them, that I have discovered this identity, or I would have pro- posed to substitute the specific names of Brongniart for those given by me in 1857. I take the first opportunity of making the correction.

GRAPTOLITES. 85

and slightly curved forward: cell-partitions usually well marked, and near the base, making a much less angle with the axis than towards the aperture.

When the funicle is broken, this species sometimes occurs like the bi- brachiate forms, as in fig. 5 of plate iv, and in that condition bears some resemblance to G. nitidus ; but its stipes are wider, its habit more robust, the cellules more curved, making a greater angle with the axis; the den- ticles coarser and more equilateral, and usually mucronate or sub-mucro- nate. No pustules at the base of the cell-partitions, as in G. nitedus, have been observed in this species. There is also a resemblance between G. patulus and this species ; but in that one the stipes are usually more slender, the denticles more mucronate, the curve of the aperture much greater, and the cells make a much greater angle with the axis.

This species is associated in the same shales with Gt. nitidus, G. exten- sus, G. constrictus, and Phyllograptus tlicifolius. I have united with this species the specimen represented in figs. 9 and 10, of plate iv, though it presents variations in some of itscharacters. A small portion of one of the stipes near the base of this shows a number of cellules or serratures equal to twenty-six in the space of an inch. Its affinities are more nearly with G. bryonoides than with any other; and having but this individual, I refer it for the present to that species.

EXPLANATIONS OF FIGURES OF GRAPTOLITHUS BRYONOIDES, Hall.

Pirate IV.

1, 2, 3. Young individuals of this species.

4, An older individual.

5. A young specimen preserving two of the stipes, the funicle having been broken.

6. An enlargement from fig. 1, showing the radicle, funicle, and origin of the four stipes, with a few of the earlier cellules.

7. An older and larger specimen.

8 An enlargement showing the character and proportions of the cellules.

9. A small individual, preserving the four stipes in part, which are somewhat more slender than the usual forms of this species.

10. An enlargement of the base of the specimen, showing the cell-denticles on one of the stipes, and a proportionally longer funicle than in fig. 8.

11. An extremely elongated stipe, the lower end showing the commencement of growth; the distal extremity is broken.

Puate III.

11. A fragment of a stipe from the rough shales, with Phyllograptus ilicifolius. In the character of the cell-denticles it resembles the specimen pl. iv, fig. 9, and with that one may constitute a distinct species.

12, An enlargement of a part of the specimen fig. 11.

F

86 CANADIAN FOSSILS.

Puate VI.

4, A frond in which three of the stipes, and the base of the fourth, are preserved. The specimen shows some peculiarity in the union of the parts by the slender funicle.

Formation and Localities—Shales of the Quebec group ; Pomt Lévis, Grds Maule, and river St. Anne.

12. GraptotitHus Bieaszyti, Hall.

Plate XVI, figures 22-30.

(PHYLLOGRAPTUS SIMILIS, Hall: Geological Survey of Canada, Report for 1857, page 140, Compare Didymograptus caduceus, Salter: Quarterly Journal of the Geol. Society, vol. ix, p. 87.)

Description.—Frond broadly oval or sub-oval, consisting of four some- what semi-elliptical stipes, which are nearly straight or slightly curved on the non-celluliferous margin, and broadly curved on the celluliferous side ; all closely united at the base in a radicle (?), and from which they are abruptly recurved. These stipes are more frequently distinct at the apex, While in some individuals they are in contact or apparently united at that pomt, but always separated in the centre for a dis- tance of three fourths their length. Entire length of specimens from four to six tenths of an inch, and width three tenths of an inch, exclu- sive of the denticles. The individual stipes, in the centre of their length, are twelve hundredths of an inch wide. Radicle undetermined. Cellules from thirty-two to thirty-six in the space of an inch, narrow at the base, gradually ascending and curving outwards, except those near the base, which are recurved: cell-margins curved, and extended in mucronate points, which are the continuation of the cell-partitions. Test thin and smooth, with the exception of the cell-partitions.

This species presents a great variety of aspects, and the most critical examination has left some doubt as to its original mode of growth. The more perfect specimens are broadly oval, the diameters about as three to four; and where the stipes are apparently conjoined, at the two extremi- ties, there is a vacant space in the centre (extending about three fourths of the length, and from six to eight hundredths of an inch in width), except that some portions of one or both the other stipes are visible. In one or two individuals, there is a linear body extending longitudinally through this space, which may have been originally the axis; but its relations cannot

GRAPTOLITES. 87

be determined. Examinations have failed to exhibit any satisfactory evidences of the existence of a radicle. In most of the specimens the stipes are united at one extremity and free at the other; while their curva- ture is such, that if continued, they would meet. In these specimens the four stipes are often distinctly seen, two usually showing the non-celluli- ferous margins; while sometimes three, and rarely the four stipes show the celluliferous margins.

The individuals are extremely numerous, but in almost all instances the characters are more or less obscured by the stipes being slightly separated by intervening lamin of slate, or by the weathering of the surface. On a single piece of slate of about a foot long by six inches wide, there are more than one hundred individuals ; but nearly all of these are so obscured by weathering, that they afford little means of determining the characters or mode of growth. In the whole collection, there are not more than one or two species of which the individuals are more numerous than of this, and in no other are the characters so indistinct.

From the deep curving cellules and broad stipes, which are often appa- rently conjoined at the apex, I have supposed that they may, at some period of growth, have been jomed along the non-celluliferous side for the entire length. On this account, I had originally referred the species to the genus Phyllograptus.

In some of the specimens, where two of the stipes are spreading, and show the celluliferous margins, the non-celluliferous face of a third stipe often stands vertically between them, like a stem. These forms resemble the Graptolithus caduceus of Salter, which was obtained by Dr. Bigsby from ‘‘ the Lauzon Precipice,” * and I have hesitated in regard to making of these a new species. The name of Phyllograptus similis was applied to such forms as figs. 26, 29, and 30; but when it became apparent that all the other varieties of form must be referred to the same, it was necessary to remove it from that genus; and since I had already named another spe- cies Graptolithus similis, I take great pleasure in dedicating this to Dr. J.J. Bigsby, who early explored the geology of the northern portion of our continent, and who, in later years, has never ceased to interest himself in American geology, and to aid in its progress.

EXPLANATIONS oF Figures or Graprouiruus Biessyi, Hall. Prats XVI.

22,23, and 24 illustrate a common condition of this species, where two of the divisions show the lateral faces, while the non-celluliferous edge of a

* This locality is probably the same with that which has furnished the greater part of the graptolites here described; the precipitous heights of Point Lévis being in the seigniory of Lauzon.

88 CANADIAN FOSSILS.

third division is seen lying nearly vertically in relation to these. The fourth division has been broken off in the separated film of slate.

25. A specimen showing the lateral faces of two divisions. Below these, in the shale, are seen the non-celluliferous edges of the two other divisions.

29 and 30 show a still closer arrangement of the parts, and the contiguity of the non-celluliferous edges at the apices, which are scarcely perceptibly separated in the shale.

26. An individual where the apices of the divisions are in contact, either conjoined, or accidentally so placed, with a narrow space in the centre. In obscure specimens it is difficult to separate such forms from Phyllograptus.

27. An individual where the divisions are equally spreading: one of them presery- ing only the base of the stipe.

28. The same enlarged.

Formation and Locality.—Shales of the Quebec group; Point Lévis.

13. GRAPTOLITHUS DENTICULATUS, Hall.

Plate IV, figures 12-16.

(G. DENTICULATUS : Geological Survey of Canada, Report for 1857, page 132.)

Description.—Frond consisting of four simple stipes proceeding from a simple radicle. Stipes slightly ascending at their origin, but immediately and strongly recurved, again bending gently upwards from the middle to- wards the extremities ; slender at the origin, and gradually expanding to a width of from nine to twelve hundredths of an inch (exclusive of the den- ticles), which it almost uniformly maintains. Substance of the stipe ex- tremely thin, and marked on each margin by a linear filiform ridge, like the ordinary solid axes of these bodies. In the impressions left on the removal of the substance, each margin shows a continuous filiform groove in the place of the thickened or solid margin of the stipe; the groove on the celluliferous or denticulate side being much stronger than that on the back of the stipe. Surface apparently smooth throughout. Cellules consisting of small mucronate equilateral denticles, placed vertically on the margin of the stipe, and rising immediately from the thickened solid edge: den- ticles spreading below, slightly curving, and united at their bases by a thin pellicle ; varying in their distance on different parts of the stipe, and apparently in different stages of growth ; sometimes twenty-four in the space of an inch, near their origin, while elsewhere the average number is from eighteen to twenty ; the lower numbermarking the strongest stipes measured.

This species is very peculiar, differing not only from the associated species, but from all others in the arrangement of its denticles.

GRAPTOLITES. 89

The specimen originally described under this name is a fragment (pl. iv, fig. 14), consisting mainly of an imprint in the shale, the substance of the fossil being preserved in some parts. ‘The solid axis on the denticulate margin is clearly defined in the impression, and in some places the substance remains, and is expanded at each denticle on the upper side so as to occupy the base of each depression. The cellules terminate in so minute a point that no aperture is visible ; but in a longitudinal divi- sion of some of them, they appear to have been hollow tubes. The back of the stipe is clearly marked (as is usual in the graptolites) by the presence of a distinct solid axis, which in no respect differs from the ridge on the opposite margin, except that the latter extends into the base of the cellules.

A further study of the collection has shown that some obscure imprints in weathered shale are of the same species. ‘These imprints, at a few points, retain portions of the pellicle, and the form of the cellules is well preserved ; they reveal moreover the mode of growth, as shown in figs. 12 and 13 of pl. iv; thus indicating. their relation im this respect to G. bryonoides andG. quadribrachiatus. The recurved position of the stipes is a feature of G. bryonoides, but less extreme than in this one. This species may be readily identified by the pointed cellules, vertical to the axis, which appear to be entirely separated from the common body, except in well-preserved portions, where in a few examples they are shown to be connected at the base by a continuation of the cell-wall above the solid axis.

EXPLANATIONS OF FIGURES OF GRAPTOLITHUS DENTICULATUS, Hall. Puate IV.

12. A small imperfect specimen, preserving three of the stipes.

13. A larger and more nearly entire specimen, showing the four stipes. Their junction at the base is not quite satisfactorily shown.

14. A part of a single stipe, in which the cellules are well shown on one part; while they are compressed and nearly obliterated on the left of the curve.

15. An impresssion of a part of a stipe which is nearly straight; the imprint of the axes or thickened margins is not defined.

16. An enlargement from figure 14, showing the form of the cell-denticles, and the

strong marginal axes ; one portion represented with the substance remaining, and the other as an imprint.

Formation and Locality.—Shales of the Quebec group; Point Lévis.

90 CANADIAN FOSSILS.

14. GRAPTOLITHUS FRUTICOSUS, Hall.

Plate V, figures 6-8; and Plate VI, figures 1-3. (G. FruTicosus : Geological Survey of Canada, Report for 1857, page 128.)

Description.—Frond consisting of two pairs of ascending and slightly curved stipes arising from the two sides of a long slender radicle, which is divided above: the stipes are celluliferous on the inner or adjacent mar- gins, little divergent at the bifurcation, and continuing for a half or two thirds of theirlength nearly straight ; above this they curve gently outwards, presenting, when not distorted, a very beautiful and symmetrical form. The stipes gradually increase in width from their origin, being at the base one fiftieth of an inch, and in the widest part one twelfth of an inch, exclusive of the denticle. The proportion of the stipe occupied by the common body is extremely narrow.

Surface smooth, or with scarcely visible striz: at the lines of the cell- partitions: axis very slender; test thin and fragile. Radicle half an inch in length. Cellules short and broad, making an angle with the axis of about 38°; the length from two to three times the diameter, and free from a third to a half of the entire length, according to their development ; variably curving in different parts of the stipe. Aperture wide, apex pointed, scarcely mucronate, and sometimes acutelyrounded. About fifteen cellules in the space of an inch, varying slightly in different parts of the stipe: near the base the serrature or length of the denticle is equal to the width of the stipe, while in the wider portions it is less than half the width of the stipe.

This species, in all the examples that have been observed, is a very distinct and easily recognized form. Wherever the radicle is preserved, it is longer than in any of the other species: this part bifurcates above, and the divisions, moderately diverging, represent what I have termed the funicle in the quadribrachiate forms; from each extremity of this, the stipes originate. All the divisions are little divergent, and the frond grows upwards like a small shrub. The form of the cellules differs from other species here described, except perhaps G. indentus, which is readily dis- tinguished in its mode of growth, as well as by other characteristics.

EXPLANATIONS OF FiguRES OF GRAPTOLITHUS FRUTICOSUS, Hall. PuaTe V.

6. A small individual with the radicle and extremities of the stipes broken off.

7, Anenlargement from fig. 6. The serratures are either imperfect or shrunken, and do not present the characters seen in better-preserved specimens.

8. An individual nearly entire, but badly preserved in the outline of its parts.

GRAPTOLITES. 91

Puate VI.

1. A fragment showing two of the stipes entire, and the bases of two others ; the radicle extending to the margin of the specimen.

2. A specimen preserving three of the stipes, one of them entire, and showing some irregularities in the bifurcation where the one is broken off.

3. Anenlargement of the right-hand stipe of the specimen fig. 1.

Formation and Localities.—Shales of the Quebec group; at the upper end of Orleans Island, and three miles above river St. Anne.

15. GRAPTOLITHUS QUADRIBRACHIATUS, Hall. Plate V, figures 1-5; and Plate VI, figures 5, 6.

(G. quapripracHtatus, Hall: Geological Survey of Canada, Report for 1857, page 125.)

Description.—Frond composed of four simple undivided stipes arranged bilaterally, or two proceeding from each extremity of the funicle. Stipes slender, very gradually increasing in width from their origin, as far as traced ; usually straight, sometimes slightly curved ; width from two to four hun- dredths of an inch at the base, and im the most perfect examples, nine hundredths of an inch at the widest part. The back of the stipe is marked by a filiform axis, and there is scarcely more space occupied by the common body. ‘Test thin, though well preserved in the finer shales. Surface of cell-walls distinctly striated parallel to the apertures, and the cell-partitions visible nearly to the back of the stipe.

Cellules narrow, scarcely curving, and slightly expanding towards the aperture, making an angle with the axis of about 38°; the length equal to about four diameters, the free portion being from one third to two fifths their entire length. The margin of the aperture is nearly straight, or very slightly curved, making an angle of from 95° to 100° with the axis. The number of cellules in the space of an inch is from twenty-two to twenty-four, dependent on the distance from the origin of the stipe, and on the degree of development. The apex of the denticle, or posterior point of the aperture, is a little below the base of the second cellule in advance. Cell- partitions thin, and usually not well preserved.

This species, when entire, is readily distinguished from G*. bryonotdes by its straight and more slender branches, and by the general aspect and expression of the fossil; it has only a remote similarity with the other quadribrachiate forms. In separated or double stipes it bears some

92 CANADIAN FOSSILS.

resemblance to G. arcuatus, except that it is less curved, and the form of the cellules is distinctive. From the other bibrachiate forms, it is very readily distinguished on comparing the form of the cellules.

I had heretofore regarded this species as possessing a disc, like G. crucifer and others ; but on examination of all the specimens which can be satisfactorily identified with it, not one has showna disc. The discs with four stipes, which are broken off so close that no serratures are visible, cannot be satisfactorily identified with this or any other species, and are therefore left in doubt at this time. They may be regarded as belonging to G. crucifer, or to the young of G. Headi.

EXPLANATIONS OF FIGURES OF GRAPTOLITHUS QUADRIBRACHIATUS, Hall. PLATE V.

1. A large specimen with stipes vertically compressed.

A young specimen in which one of the stipes appears to be subdivided.

8. An individual with stipes a little curved, the back of the stipe visible, and showing no serratures.

4. A frond with one of the stipes broken off; one showing the cellules and distinct striz parallel to the cell-partitions, while the other two are turned so as to obscure the cellules.

5. An enlargement from fig. 1: the stipe has been vertically compressed, causing the cellules to show a less angle with the stipe than in the normal condition.

PuaTeE VI.

5. A frond preserving one stipe partially entire, and others broken off: the funicle and radicle-point are well preserved.

6. An enlargement from the specimen fig. 5, showing the form and proportion of

cellules in their more perfect preservation, with the striz parallel to the cell- margins well preserved.

Formation and Locality.—Shales of the Quebec group; Point Lévis.

16. GRAPTOLITHUS CRUCIFER, Hall. Plate V, figure 10. (G. crucirer: Geological Survey of Canada, Report for 1857, page 125.)

Description.—Frond composed of four simple, strong stipes, united at their base by a small thickened disc. Stipes strong at the base ; the two pairs connected by a short funicle, which is without a visible radicle.

GRAPTOLITES. . 93

The specimen