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U > I
K-
McGILL UNIVERSIT
PAPERS FROM THE DEPARTMENT
OF
Geology.
•(vitii
Nc. 4.— Fossil Sponges and Other Organic Remains FROM THE Quebec Group at Little Metis.
BV
Sir J. William Dawson, C.M.G.
:!#
With Four Plates.
[Reprinted from the Transactions of the Royal Society of Canada, Section iv., 1896, pp. 91-121.]
Montreal, 1897.
^
t^BCTION IV. l.SW.
[91]
Tbans. R. S. C.
VI. — Ailditionol Noti'S; on Fossil S/i'ou/rs nml athir Ori/diiir h'ciiitiiii the Quebt'c Group of Littlr Mcfis^ aii the Loicit St. Ldirri m'l.
By Sir J. WrLLiAji Dawson, LL.D., F.RS.
With Notes nil S'lwc iif the Specimevs by I>r. (r. .1. Hinde, F.l'.S.
(Rend May 20, 18JK5.)
I
[1. Intvotliu'tory ; II. Subdivisions of tbe (^uoboc Grou^) ; III. Littlo
.Metis iiay ; IV. General Remariis on the Fossil Sponges; V. Notices of the Several Species ; VI. Other Animal Remains ; Conclusion.]
I. — Introductory.
•
The jiresent paper is a continuation of that on the same subject contributed to the Royal Society of Canada in 1889, and published in its Transactions for that year. It is intended to bring the subject up to date with reference to discoveries of new species and additional facts us to those previously known, and also to tix more definitely the age of the beds containing the fossils, more especially in connection with the more recent observations of the otttcers of the Geological Survey of Canada.
The (Juebec Group was instituted by Sir VV. K. Logan, and described by him, in 18t)3, as a peculiar coastal and Atlantic development of the formations known in the interior of North America as the Calciferous and Chazy membei-s of what was then known as the Lower Silurian system.' Logan undei-stood that on the submerged continental plateaus and ocean depths of any given geological period there must be local as well as chronological ditt'erences in the de]josits, and that the terms applicable to the foi'mations in the inland seas, which in times of continental depression covered what are now interior continental plains, cannot rightly designate those laid down contemporaneously on the borders of the open and per- manent ocean. We now know that these last are the most general and continuous i-ecords of the history of the earth, though the continental deposits, depending on subsidences alternating with elevations, give the most decidedly graduated scales of geological time in their successive and apparently distinct dynasties of marine life. Hence the plateau deposits
' Geologj' of Canada, p. 205 «;< seq. ; Appendix to Murra.v".s Report on Newfound- land, 18(J5, quoted by me in .Journal of London (ieoloKical Society, 1HS8, p. 810, and in Canadian Record of Science, 1800, p. V.io,
92
ROYAL SOCIETY OF CANADA
are the most easily available as jfeologieal chroiioiueters. and have In'on HO used both in Europe and America ; but they do not aceurately repre- sent the series of ehangeu going on in the great oeeanie areas and their
BSrt-
Viewed in this way, Logan's name, Qnehec (iroup, designates the oceanic deposits formed on tlie Atlantic border of Nortli Ameriea at u time when very different conditions prevailed in those now inland areas which afforded the elassitieation of the New York Survey. The fact of this great ditlerence remains, and the tei'm designating it will continue to be of value to geologists, so long as they are desirous rtuionaliy to corre- late the sequence of formations in America and in iOuro^ic, and to connect with their science those great facts of paheogeograjjiiy wliich enable us to realize the diverse conditions of the deju'essed and ehjvated portions of the earth's surface in diti'erent geological times. The name is fartlier justified by the fact that the lower })()rtions of our great St. Lawrence river follow a course in the Province of (Quebec wliich enables them bet- ter than any other section in America to illustrate the diHerence between the depo^■ s of the Atlantic and continental areas in the earl/ Paheozoic period.
I regard the.se consiilerations as of great importance in relation to the fossils described in this paper, because they are members of a fauna of almost univei'sal oceanic distribution ; in its time extending continu- ously over vast spaces and periods, aiul serving to bridge over the gaps in the broken series of the continental plateaus. It is likely to gain in signiticance and in relative value as science advances; and, when more fully known and appreciated, to do much toward reniedj'ing that imper- fection of our geological record, which depends, to some extent, on our basing it on localities where physical disturbances have interfered with the continuity and orderly succession of life. It is only by the patient and long-continued study of the formations deposited on those parts of the permanent oceanic areas available to us, that we shall ultimately be able to trace back the marine life discovered by the dredgings of the •'Challenger," to early geological times.
When Logan commenced his survey of Canada in 1842, little of this was understood, and he had before iiim the task of solving the enigma of original ditferences of deposits and suiierailded mechanical disturbances in Eastern Canada, with the wholly inadequate key atlorded by the inland aeries of formations worked out by the survey of New York, which itself, when it came into contact with the marginal series, became involved in that Taconic controversy, which has scarcely yet subsided, and which must remain in some degree unsettled as long as geologists fail to see that they cannot force into one system the dis.'<imilar formations of the ocean and of the continental plateaus. 1 have no wish here to dwell on tliese controversies ; but may refer for some statement of my views on the great
[DAWSON] FOSSIL srONGES AND OTHER OrtGANIC REMAINS
93
natural facts which underlie them, to the publications named in the foot- note to this section.' f <
&
lys
II. — Subdivisions ov the liuEHEc Giioui'.
Confining ourselves to the sections on the south whore of the Lower St. Lawrence, the subdivisions, as worked out by Logan and Jtichardson and more recently by Klls, with the aid of Whitea\'»'H in regard to the Trilobites, Bi-achiopods, etc., and of Lapworth'^ and Ami in the grapto- litic fauna, may be stated as follows in ascending order : '
1. The Sillery Si'/'ies, seen at the Chaudi6re Eiver, near Quebec, and also at Matane and Cape Rosier, as well as at Little Mdtis. Among its characteristic fossils are the little brachiopod Obolella (Linnarssonia) pretiosa, Billings, and Dldyoncma saciale. of Salter {D . flabellare of Eich- wald), also species of Bryo(jraptiis and Clonoijraptus. The prevalent rocks are grayish sandstones anil conglomerates with shales of red, gray and black colours, and more rarely bands of limestone and dolomite. It may be regarded as the base of the Quebec Group proper, and as the equivalent of the Calciferous of more western districts and of the Tremadoc of Wales, and perhaps as the highest member of the Cambrian system.
2. The Levis Series ; to which belong the shales, limestones and conglomerates exposed at Levis, opposite the city of Quebec, and which has been recognized as far east as Ste. Anne des Monts. Its most charac- teristi • fossils are graptolites of the genera Phylhnjraptus, 'Tetnujraptus, etc., most of which are described by Hall in his classical monograph on this fauna ; while its Trilobites, etc., have been studied by Billings, and catalogued by Ami, who separates the fossils found in boulders in the conglomerate from those properly belonging to the formation.* This series is in the horizon of the Upper Calciferous and Chazy, and may be regarded as equivalent to the English Arenig and Skiddaw.
3. The Marsouin Series ; found at that place and at Griffin Cove, White Hiver, and elsewhere, and heading graptolites of the genera Diplo- graptus, Cmioyraptus, etc. It is apparently of Chazy-Trenton age and equivalent to the English Bala.
4. Still higher beds holding Biployraptus pristis and other forms characteristic of the Utica shale, and therefore newer than the Quebec Group proper, occur west of Marsouin River, near Tartigo River and elsewhere. At this period, owing to the subsidence of nor'.hern land, the
' Appendix to Harrington's Life of Sir William Logan, p. ^XA et aeq. ; On the Eozoic and Palflaozoic Rocks of Eastern Canada, .Tournal London Geol. Society, 1888 ; The Quebec Group of Logan, Canadian Record of Science, 1890 ; Salient Points in the Science of the Earth, 1894.
* Transactions Royal Society of Canada, 1886.
* For notices of previous work and recent discoveries, see Report by Ells, Geolo- gical Surrey of Canada, 1887-88.
* Report Geol. Survey of Canada, 1887-88.
Sec. IV., 1896. 6.
94
ROYAL SOCIETY OF CANADA
i^uelu'c (Iroup torKlitions of cold wutrr Jind imuldy de|)<);?its ovcrs]>i'oad the whole intorior of the contiiieiit. thus ltk'iidin;f the oceanic and plateau oonditioiiH for a time, and forming the natural close of the Quebec (Jroup. because temporarily obliteratiii<; the geographical distinction on uhich it is based.
III. — Little Mktis Bay.
The author of this paper has had occasion for many years to sjiend i\ portion of the sumpier at one or other of the health-resorts on tie Lower St. Lawrence, and has latterly ]»referred Little .Metis, as one of the most |)leasant in its atmosphere and surroundings. He has there natur- ally endeavoured to familiariice himself with the rocks and fossils acces- sible in walks or short drives and boating excursions, and to devote some time and labour to any locality which seemed unusuall}' jiromising.
At Little Metis, and indeed along the whole coast between the city of Quebec and Cape Rosier, a stretch of about 350 miles, the shore on the whole follows the strike of the great mass of sandstones, shales and conglomerates of the Quebec Group and which are everywhere thrown into sharp anticlinal and s^-nclinal folds, and often repeated by longi- tudinal faults, while they are also much disturbed by transverse faidts and flexures.
These older rocks are covered in places with the sands and clays of the Pleistocene period, locally containing marine shells, and accompanied with vast numbers of gneiss boulders from the Laurentian Mountains of the north shore, here about forty miles distant, and with occasional, but often very large, blocks of Silurian limestone from the hills to the south- ward. Though masked on the lower grounds by these superficial dejxtsits. the older rocks appear everywhere in the hilh- ridges and in the coast cliffs and reefs.
Little Metis Bay faces the northeast, and its outer boundar}' consists of a strong gray sandstone forming the Lighthouse Point and extending to the eastward in a long and dangerous reef, which it is hoped may. at some future period, form the basis of a harbour of refuge for shi|)ping. Immediately to the southwest of the point, the shore recedes rapi Ih" (see map"), the sea having cut back along the outcro])s of dark shaly bands which overlie the standstone, the whole di])])ing to the southward. These occupy the northern division of the bay, about half a mile in width. South of this a second reef of sandstone divides the bay, rising into a high bluff, known as Mount Misery. This is divided hyy a shallow cove, and at its southern extremity there projects i low |)oint of sandstone and con- glomei'ate, which seem to extend eastward on a little outlying island and a submerged bank, on which the sea breaks at very low tides, anil which connects it with another and highe • islet about two miles distant, called the Boule Rock. This consists of sandstone and conglomerate
[daw£jon] fossil sponges AND OTHER ORGANIC REMAINS
98
(lippinfjf southward at a hi^h an^le. South of the point above mentioned, the shore a^ain honds rapidly westward alon<>; a belt of dark shaly beds, and forms the southern and narrower division of the bay. almost dry at low tide, and into the southwest corner of which the Little Metis River flows. From this southwest anjrle of the bay another bed of very hard sand6.1one eap])ed by conglomerate extends along the coast to the north- eastward, and after a break reappears beyond Tun-itf's Hotel, in the clitt'of the Crow's Nest, from which at a lower level it continues for some distance towaril Sandy Bay.
sf4.
,.»■»
RIVER STLAWRt^l^^
SaneA/one &Oanotor,.9rale Shale
P"^
Sketch-map of Little Metis Bay and vicinity, siiowing locality of Fossil Sponges. (Scale about two inches to a mile.) Geographical line.s from a map by Dr. Ells.
Sectional view on the beach north of the church, represented in the sketch-map.
(Length about 5.50 feet.) {A) Conglomerate. (B) Sandstona or quiirtzite. (C) Olive arenaceous shale. (i» Black shales, with some olive bands and thin layers of hard, arenaceous dolo- mite ; remains of sponges in a few layers. (E) Muddy shore : indications in places of soft, dark shale. (F) Hard, gray and olive shales, with bands of dolomite and sandstone. (6r) Pleistocene sand and boulder clay.
The whole of these beds have southerly and southwest dips, though in places they become vertical and contorted. These disturbances, how-
\
96
ROYAL SOCIETY OF CANADA
ever, 80 far as can be ascertained, are local, and do not affect the general ar- rangement, ;>xoe])t in so far as slips parallel to the strike may repeat the beds.
The layers holding fossil sponges, to be described in the sequel, are Been in low reefs or ledges of black and olive shale, extending along the Bouth side of the bay from near the mouth of Little Metis Jiiver for about a furlong to the eastward, and are quite regular and undisturbed, though inclined at an angle of about 50°. The sandstone and conglomerate im- mediately overlying confornuibly this band of shales is capped with boulder-clay and sand, and forms the rising ground on which stands the Wesleyan church, indicated on the map. The section given on p. 95 shows the attitude and nslation of these beds, and is drawn from the church to the northwestward.
Before proceeding to describe the eponge-beds and their fossils, it may be well to notice the overlying sandstone and conglomerate, and similar beds in the vicinity, with the fossils they contain, and the rela- tions of these to other beds on the Lower St. Lawrence.
The upper sandstone {li in the section) is so hard that it might be regarded as a quartzite, differing in this respect from some of the other beds in the vicinity, as, for instance, those of Mount Misery and the Lighthouse Point. It dips S. 20° W. magnetic, at an angle of about 50°, and is about sixty feet in thickness, though apparently thinning to the eastward. Its lower side is i-emarkably flat and even, and has been
undercut by the sea.
owing
to the softness of the shale below. On
its strata planes are many fantastic, radiating forms indented on the weathered surfaces, and akin to those which in the Cambrian quartzites of Nova Scotia I have named AstropoUthon} No other fossils have been observed in it. In tracing this bed to the eastward, it is seen to be over- laid by, and to pass into, a very coarse conglomerate, with an arenaceous paste and partly angular or rounded boulders, some of them more than two feet in diameter. Some are of a light gray limestone, others are quartzite, sandstone and indurated slate. Some of the limestone boulders hold fossils, and from one of these I obtained the following form;:, kindly identified for me by Mr. Matthew :
Pleurotomaria 'i
Iphidea bella, Billings.
Hyolithea (species).
Branching organism (possibly a sponge).
Fragments of various small Trilobites.
Olenellus Thompaoni, Emmons. Ptychoparia Metisaica, Wakott.'^ P. (species). Protypua aenectua. Solenopleura (species). Stenotheca rugoaa, Walcott.
These fossils are all, so far as determinable, of Lower Cambrian age, and must have been derived from limestones already undergoing waste
' Acadian Geology, Supplement, 1878, p. 82.
'•* First found some years ago in a similar boulder from the Boule Rock. Along with it was found a small sponge, Trachyum vetiiatum, described and figured by Walcott in his memoir on the Lower Cambrian.
[DAWSON] FOSSIL SPONGES AND OTIIEll ORGANIC REMAINS
97
lit the time of tho Quebec Group. Thus, thouirh the coni^lomemte over- lies and irt newer than tho shales holdinj^ sponi^es, the limestone boulders contuincd in it an; of muoh greater atfo. It has loiii^ been well known that similar ai»])oarances oc(^ur in nearly all the limestone confflomerates of the Quebec (rrouj), and at tirst they led to serious difticulties as to tho age of the fornuition. Sometimes they are very deceptive. I have seen in tho conglomerate at St. Simon a slab of limestone, eight feet in length, which might readily, in a limited exposure, 1)0 mistaken for a bed in place, but which is really a Lower Cambrian boulder containing numer- ous fragments of OlenoUus and other ancient Trilobites, and several species of IFvolithes.
These g. ,t and irregular beds of conglomerate would appear to indi- cate ice-action in the Lower Paheozoic sea, and it would seem \hat the boulders must have been denuded from reefs of older Cambrian rocks now mostly covered up or removed by denudation, while, unlike tho condition of things at tho time of the Pleistocene drift, no Laurentian material seems to have been accessible.
Up to 1887 the beds in Little Metis Bay had been very unproductive of fossils. They had atlbrded to the late Mr. Eichardson the little Lin- narssonid pretiom, and I had found in the sandstones of Mount Misery and the Lighthouse Point a few fragments of a /{etiolitcs, apparently R. cnsifonnis of Hall, and in the shales near the Lighthouse Point abun- dance of worm trails, some of the typo of that described by the Swedish geologists as Arenicolites spiralis. In so far as these fossils afforded information, they tended to refer the whole series to the lower part of the Quebec Group, and, as it seemed to be an ascending one to the south- west, the impression conveyed to me was that the black shales near the upper part might belong to the base of the Levis series. As already stated, however, the new facts ascertained respecting the position and fossils of the Sillery series now tend to the conclusion that the whole belongs to this lower member.
For detailed sections of the productive sponge-beds I may refer to my paper of 1889, merely remarking here that in a band of shale, with a few thin layers of dolomite, the whole more than 100 feet in thickness? onlj' three or four layers, each from one to three inches in thickness, have been productive of fossils.
IV. — General Kemarks on the Fossil Sponges.
The discovery of fossil sponges at Little Metis Bay was made by Dr. B. J. Harrington, F.G.S., in 1887, in examining loose pieces of black shale washed up on the beach. On searching for these shales in sifu, they were found in low reefs on the shore at about half-tide level, and diligent search disclosed the fact that in a few thin bands of shale sponge remains were abundant, though from the extreme delicacy of their spicu-
98
ROYAL SOCIETY OF CANADA
lar skeletons they wei'c not easily recoi^nizeil, except in a brii^ht li<:;lit and on the moistened surlaces of the shale. In that and subsequent years I undertook detailed collec'tin<>: in these beds. The thin productive lay- ers heiuif inclosed in ledges of compact shale, much material had to be quarried awaj' in order to obtain access to them, and the work could be carried on only at low tide. The best method of proceeding was found to be to trace the fossiliferous layers along the ledges, and having quarried out as ge slabs as possible, to convey these to where they could be split up and examined at leisure. By pursuing this method sufficient quantities ol' material conld be obtained to enable satisfactory compari- sons to be made. The method, in short, was the same which 1 have pur- sued in collecting delicate fossil plants and the smaller animal remains from the Devonian and Coal formation, and which has enabled .so many species of delicate vegetable organisms from Gasp^ and Nova Scotia to be restoi'cd in their external forms.
The facts observed up to 18.S0 were detailed in the ]»aper of that date, in pre[)aring which I was indebted to Dr. (i. .1. Jlinde, F.R.S., the author of the British Museum Catalogue of fossil sponges, ana of so many valuable ])apers on these organisms, for most imi)ortant information as to the structure and ))robable affinities of the s[)ecies. In addition to the notes of Dr. Hinde given in the previous jiaper. I am indebted to him fo.- further important suggestions contained in these i>ages, and for the description of an additional .species.
Since 1889 excavations havo been continued from time to time, with the view r.ore partAularly of discovering new species and of obtaining more |)erfect examples of those previously known. In noticing the results obtained, I shall tii-st refer to certain points relating to mode of occurrence which have been more definitely settled, and shall then present a catalogue of the species, with short descriptions and figures.
In regard to the figures. I ma\' explain that those in the text are of two kinds: (1) Camera tracings, slightly enlarged, of the picules, as seen under the microscope; (2) Restoraticms, mostly based on combining several more or less comjtleto specimens. Those in the plates are produced from enlarged photographs taken usually from moistened surfaces under a bright light. The.se were printed and carefully retouched to render them more distinct, then ivproduced in negatives of or near to the natural size, and copied from these for printing. Those which were sufficiently distinct for this, were reproduced without being touched.
In the former ])aper, of 1SH9, Dr. Hinde ably discussed at some length the state of preservation of the s})ecimens. He remarks that the skeletons of the greater number of the species were ma''e up of delicate spicules, often cruciform, and arranged in such a manner as to form a thin lattice-like framework inclo.sing a hollow s)tace or sack, and siipjjort- ing the soft animal membranes. In the meshes of this framework, and
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
99
sometimes forming an external dermal coatinu;, were minute spicules and delicate ))rotective spines. The spicules, originally composed of amor- ))hous 01- colloidal silica, are now for the most part entirely replaced by pyrite, and not infreciuently they arc also encrusted with a delicate coating of minute crystals of the same mineral, so as greatly to incieaso their ap])arent magnitude, though in most cases it is possible under the lens to distinguish the original spicule from its coating. The sponge thus ajjpcai-s as a delicate bronze-coloured framework or mass of spicules on the surfaces of the shale. In a few instances the spicules have retained their primitive siliceous material, and more rarely tiie nniterial of the spicules has l)ecn entirely removed, leaving their imjyressicms merely on the matrix. It sometimes hap])ens, especially in the case of species with somewhat dense 8picu;nr walls, that the meshes included in the spicular framework are tilled in with pyrite, so as to show merely the general form and faint indications of the spicular structure.
Originally rooted in the soft ooze of the sea bottom, the specimens seem sometimes to have been buried in xitu, so that when the shale is s[)lit t''ey appear in transverse section or as round tlattened discs; but in most cases they seem to have drifted from their anchorage, either with or without their anchoriiig-rods, and to have lieen flattened later- ally. When entire, they sometimes ])i'esent, when the shale is split ojien, a surface of dermal spines, masking the skeleton ])ropei\ In other cases the dermal s])ii\e8 come away with the matrix, leaving the skeleton spicules exposed. Thus the same species may presen* very difll'erent appearances under difl'erent circumstancos. In most cases the body of the sponge has been more or less disinttgrated or reduced to ])atches of loose spicules, and some large surfaces ai'e covered with a confused coat- ing of spicules and anchoring-rods belonging to several species. In some cases also the loose spicules, or fragments of them, seem to have been gathered in little oval or cylindrical piles and inclosed in pyrite. At first I was disposed to regard these as coprolitic ; but Dr. Ilinde doubts this, and i-egards them as merely loose spicules drifted together into hollows or worm-burrows.
All these differences of preservation and ex|)osure ])resent consider- able difficulties in discriminating the species; and these are scmietimes increased by the associatitm of 8])ecimens of different ages. It thus requires experience and abundant material to obtain definite I'esults. Nevertheless Dr. Ilinde, who has had very extensive acquaintance with fossil sponges in various conditions of preservation, makes the following remarks in reference to the specimens submitted to him :
•'The Metis specimens are specially interesting, since they throw much fiesh light on the character of the earliest known forms of these organisms, and their discovery is the more op])ort»nie from the fact that our knowledge of the existing hexactinellid sponges — the group to which
100
ROYAL siUCIETY OF CANADA
all. or nearly all. tlu'so fossils l)eloni>; — ims i urn vastly increased bj- the Avork of Prof. F. E. Seliul7,i'. of Berlin, on the hexaetinelled sponifes (lre(l<i;e(l up hy tlie Challeni>er P^xpedltion, and thus we are now better enabled than idfherto to compare the fossil and the i-ecent forms.'
Tlie conditions (»f accumulation of the Metis shales seem to have been very favourable to the ])vritization of orijanic remains. The sliells of Linnarssonia. small frai;-ments of Trilobitesand frondsof Alga', seem, all alike, to have been amenable to this change, and cylinders and spirals of solid crvHtalline pyrite occupy the burrows of worms, while nodules of the mineral destitute of any organic form also occur. On the other hand, in some layers containing fossils, there is no trace of ]ivrite. but in these it is very ditticult to see the spicules, owing to their similarity in colour and lustre to the sla*e.
V. — NOTUKS OK THE SEVERAL SPECIES.
The arrangement of Palaeozoic fossil s|)onges is still to some extent provisional. That adojited below is the (me most current at present, and necessarih' depends entirely on the material and structure of the skeleton.
Viewed in this way, the whole of our Metis sponges, if we except a few uncertain forms to be mentioned in the secjuel, belong to the order Silicca, including those which form their skeleton of siliceous needles or spicules. Under this are sponges with simjilc spicules (Monactinellids), and these seen', to be the oldest of all, since the needles found in the Ilunmian cherts and those recognized by Mr. Matthew in the Laurcntian a])])ear to be mostly of this type. Others (Hexactinellids) present cruci- form spicules, or spicules with six rays, ])laced at right angles to each other. The.so are arranged so that tlie i-ays ar<' joined by their points, forming very com]tlex and beautiful frameworks, the variety of which is inci-eased by the fact that the ditterent i-ars may be unequally de- veloped, or some of them may be abortive, giving forms available for a great nmny beautiful constructive uses. We shall tind that the com- plexity and diversity attainable by spiculai- forms, all based upon one general law, but admitting of countless ditferences and moditications, had already nearly i-eadiecl its nuiximum in a very early geological period.
The Hexactinellids may again bo divi<led into two groups, acioi'ding to the united or loose condition of ihe spicules. When these are tirmly cemented together by siliceous matter, we have the group Dicfyonma, and when they are united merely by animal matter, and consequently fall asunder on decay, they belong to the gi-oup /jjjssdkina. Under these we have families, genera and species.
The following list is u revision, with important additions, of that given in 1889.
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
101
Order SILICEA.
Suborder Hexactinellida.
Gnnip Lyssakina.
Family Protospongid.e. Hin(k>.
Genus PROTOSPONGIA, Salter.
This genus was established by the hite Mr. Salter fi*om some remains of lattice-like spicular bodies found in the Middle Cambrian of Wales, and which, thougli fragmentary and obscure, that eminent naturalist was able to refer to the group of Siliceous sponges. The genus includes several of the Metis species, which have enabled us to complete the characters of Salter's genus.
1. — Protosponoia tetranema. Dawson.'
(Figs. 1 to 5. PI. I., Figs. 1 and 4.)
+ ¥4-
Fni. 1. — Pro(ospongia tetranema. A small specimen restored.
Fi(i
'L—Protospongia tetranema. Anchor- ing-spicules slightly enlarged.
In the specimens in which the outline of the sponge has been pre- served, the body appears to have been roun<led or broadly oval. There was an aperture or osculum at the summit, though it can be distin- guished only in a few specimens. The wall of the sponge appears to have consisted— as in the other species of this genus— of a single layer of cruciform spicules of various dimensions, disposed so as to form a frame- work of quadrate or oblong interspaces. The rays of the larger spicules constitute the boundaries of the larger squares; but owing to decay
1 The characters of this and several of the following species were given in " Notes on Specimens in the Peter Kedpath Museum," and in the Transactions of the Royal Society, 1880.
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ROYAL SOCIETY OF CANADA
and fliittoniiin tlu' spicuk'S are usually nnich displaced. Within thewc, st'rondarv and smaller S((uares are marked out l»y smaller spicules, Judi^ini^ Ity the loiiifth of the rays of the la rger spicules, the larger squares would he ahout 4 mm. m diameter, whilst the smallest do not exceed
Fn;. '.i.—Protospotij/ia tetranrma. Priiniiry, secondary and tertiary cruciform spicules, x 5.
1 mm. The rays of the individual spicules seem to have heen united merely hy the animal matter, and not by a silicious cement. The osculum is protected hy defensive spines (Fig. 4). and in young specimens these are often very numerous. The rays of the larger spicules are conical, gradually tapering from the central node to the pointed extremity ; whilst the rays of the smaller spicules appear to he nearly- cylindrical.
From the base of the sponge, four slender, elongated, filiform rods pi'oject. They are api)ro.\imately cylindrical, pointed at both ends, very slender, and from 50 to TO mm. in length. Their proximal ends are inserted apparently in the basal part only of the .sponge. In perfect s])ecimens they are seen to approach and cross each other in the middle, and then to diverge, finally again approaching and forming a loop with a minute central point. So many examples of this structure have now
sf
'%^t^4#
Fig. A.—Protosponffia tctrancma. Osculum enlarged .
and surrounded l)y minute spicules. Fm. o.— Anchoring-rods.
been found that there can bo no doulit as to its true mitui-e, though in a few instances the loop has broken asunder, leaving the rods free. Kven in this case, however, the}' show their curveil emls (Fig. 5).
I
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
103
This is one of the most abuiKhint species at Little Metis. Thore can he no hesitation in phicing it in the i^enus Protospomjia, since tlie same avvangenient of the spicular mesh-work is present in it as in the type of this ifenus. In the earlier examples of the i^eiius, however, the presence of anchoriniii-spicules was not recognized, owing, no doubt, to their imper- fect state of preservation, and this feature nniy now he i-eckonetl as one of the generic characters. In the present species, however, these anclior- ingspicules were very peculiar, and seem to l)e rays of a cruciform spicule, which were bent upward and lengthened, forming a stalk for the sponge. This would give a firm attachment, and adapt itself to the gradual risi' of the bottom to which the sponge was attached. The mechanical pi'ojtertics of such an arrangement of spicula are obviously well suited to ett'ect their purpose.
Some further remarks on the /yssakiiw character of Frotospomjia will he found in the paper of 1889, and the moi'e recent collections also show that the skeleton spicules, at fii-st small in the young specimens, grew in length, by additions to the ends of the rays as the body increased in size.
2, — Protospongia mononema, Dawson.
(Figs. 6, 7 and 8. PI. I.. Figs. 2 and 3.)
Fig. Q.— Protospongia Fio. l.—Protonjmnqin monovema. Cruciform and
mononema. Restored. protective Hpiciile.s, x 5.
General size about one inch in diameter, originally globular but now flattened. Body spicules cruciform and more slender than those of
m»
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ROYAL SOCIETY OF CANADA
P. tcfrtinema. Superficial or del'onsive spicules very numerous and some- what long and slender, so as to give a liirsute appearance, and in flat- tened specimens often to obscure the body sjiicules. Eoot, single, stout, often three inches lonj,;, witli two to four short, spreading branches at base. These terminal spicules are flattened at the extremities. The
Fig. 8. -Pi'otosponffia mononema. Primary, secondary and tertiary spicules, x n.
anchoring-rod in tliis species is often increased in thickness by a crust or frosting of pyrite, and this would seem to indicate that it had, like tlie modern Hyalonema, animal matter as well as silica in its composition, or that foreign organic bodies attached themselves to it.
Nearly as abundant as the preceding form, wliich it differs from in the character of the anchoring-rod. each of which may be regarded as a single elongated anchor-shaped spicule, with five rays. The skeleton Bpicules ai-e also more slender and delicate, and their rays longer, and there is a greater development of protective dermal spines. The osculum is narrow and with many long defensive needles. (Plate I., Fig. 3)
3. — Protosi'ongia polynema, Dawson. (P^igs. !» and 10.)
Fig. 9. — Protonponqia polynema. Portion of base of large specimen.
A large sponge in great shapeless flattened patches, boveral inches in diameter, though there are smaller individuals also. Body spicules fine and slender, making a very open mesh. At base numerous simple root
[DAWsoNl FOSSIL SPONGES AND OTHER ORGANIC REMAINS 103
spicules, short, and. in some cases, expaiuied at llioir extremities. Youn^ individuals seem to have been glolnilar and pi-oluihly se„.sile, while large individuals had a flat base; but the general f'onu is greatly obscured by crushing, especially in the larger specimens.
Fig. m.—Protospungia polynemai Primary, .secondary and tertiary spicafes, x 5.
4. — rROTOSPONGIA DELICATULA, DaWSOn.
(Figs. 11 and 12.)
Globular or oblong in form, 1 to 4 cm. in diameter. Body spicules cruciform, regular, forming a very dense mesh, about 1 mm. or less in the o[)ening. Osculum probably wide. Defensive spicuies very short and close. Several short anchoring-rods. Some indications of a double row of spicules in the body-wall. The density of the spicular body-wall causes it often to be encrusted and obscured by pyrites.
Fio. 11.— Protosponyia delicatula. {a) Re- stored. (6) Portion of base enlarged.
Fig. 12.— Primary, secondary and tertiary spicules, x 5.
Rauff, in his monogra])h on fossil sponges, identifies tliis with Wal- cott's Ct/athophycus {Teijanium) subsphcericus of the Utica shale, but com- parison with specimens kindly furnished by Dr. Walcott shows that there
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ROYAL SOCIETY OF CANADA
18 no f^round for this except a i-eseiiililance in Lfoneral form. The strut- tums, 80 far as known, are quite ditt'crent.
Note. — The two followini; species, haviutf tlie row.s of spiciiles diagon- ally arrauired. as I remarked in de.seriltinjf them in 188'J. have l)een placed hy Eautf in a new i^enus Diagonivlld. I douht the expediency of this on the mere ground of divergence of the rows of rae.shes from horizontality. But tlieiv are other peculiarities of these sjiecies. which miglit fairly entitle them to constitute distinct sections of the i;-enus, 1 therefore, i»lace them hy themselves, noting these ditferences :
5. — Protosi'Oncua CORONATA. Uaw.son. (Figs. 13, U and 15. PI. 11., Figs. 5 and G.)
Fi(i. \'A. — Pfotonpongm coro- nafa. Restored.
Fi(i. H.—Protospongia coronata. Primary, second- ary and protective spicules, x 5.
Body ovate. 2 cm. long, hut fragments indicate that it grew much larger ; sjiicules coarae and four-rayed, so connected as to give tlie appear- ance I)}' their t)hli(|uity of a diagonal netwoi-li of rhomliic openings. This may possihly he the effect of flattening. Numerous small cruciform flesh spicules, Eoot spicules strong, short or hroken off. 2 to 4. Osculum
Fig. 15.
-Protoaporiffia coronata. internal cavity.
Showing
large, terminal, covered witli a conical hood made u]i of curved s]iicules converging to a point, and 1 cm. in height, in the smaller specimens, in which alone I have seen tliem, the larger sjieeimens heing usually imper- fect. Short protective spicules visihle at the sides.
5 =
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS ♦i. — Protohpdncha cyatiukobmis, I)aw.son. (Figs. 15 and 16. PI. II., Figs. 7 and S.)
107
¥\Q. \b.—Protoapongia cyaihi- Fig. IQ.—Protoapongin ci/nfhifoniiis. Primary, formia. Restored. secondary and tertiary cruciform spicules, x 5.
General form inverted conical. Wlion mature aitout 3 cm. wide at top and 5 em. long, without the anehoring-spicules, which arc sometimes very long. Top truncate as it' with a wide osculum, with defensive spicules on its margin. Primary spicules cruciform, with long rays, in some 2 to 3 mm. in length, placed diagonally. l()Osely attached or free, hut forming large rhorahic meshes ; secondary and tertiary spicules numerous and delicate, with slender arms. Root spicules simple, some- times very long, five or more visible in the most perfect specimens, and passing uj) to the middle of the body. Indicati<tns of many interior minute flesh spicules, often constituting a pyritized mass, obscuring tiie meshes.
The oblique character of the transvei-se spicules deserves notice, but this may be the result of compression, though I think it more likely tliat it is an original feature.
This species is well characterized by its form, and by its multitudes of very minute ci'uciform spicules. These and the fact of the sponge being often represented l)y a dense, pyritous mass, indicate a thicker and more fleshy body-wall than in some other species.
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ROYAL SOCIETY OF CANADA
Genus HYAL0ST?:LIA, Ilinde.
7. — IIyalostki-ia Metissica, Dawson.
(Fi^t?. 17. IM. III., Fig. 10.)
Fio. ll.—Hyaloatdia Metissica. Spicules x 6.
General form broad, with a lai-ge osculum and a number of stout anchoring-i'ods. Body-wall I'ornied of single long slender rods, woven into a very loose mesh and supporting cruciform and other spicules of varied form, attached only by the soft membranes, so that they are almost always found loose and disarranged. Up to 1889 I had seen the species only in this condition ; but was so fortunate in 1895 as to find a small specimen retaining its form, which 1 have figured ir Plate III., Fig. 10. The spiral anchoring-rods figured with this species in 1889 really belong to Palseo- saceus, which at one time I was disposed to connect with Hyalostelia, but am now convinced that they are altogether distinct, though Hyalostelia may form a connecting link between the Protospongidro and the Dictyo- spongidie, Us body-wall being formed not of cruciform spicules, but of long slender and single rods woven together into square or rhombic meshes.
As to the use of the generic name Hyalostelia for this species, I am, by no means certain, since the sponges included previously in that genus are very imperfectly known to me.
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
109
Family DicTYOspoNOiDyK, Ilall.
Genus CYATIIOPIIYCUS, Wakolt.
8. — Cyathopiivcus Quebecense, Dawson.
(Figs. 18 and 19.)
Fig. l8.—Cyathophycus Quebecenne. Fio. 19.— Cyathophyetis Quebecense.
Restored. Base enlarged.
Form elongated conical, composed apparently of numerouB long, vertical spicules, crossed l>y horizontal or annular hars, and with a few cruciform spicules in the meshes. The vertical and transvei-se spicules may be ci'uciform spicule^j arranged vertically. The form terminates downward in a blunt point, with indications of a few short anchoring- . spicules. This species closely resembles Ci/nthophynis reticulafum of Walcott from the Utica shale, but ditlers in detail, especially in (he sim- plicity of the vertical rods and development of the transverse or circular bai"s. The largest specimens are 8 cm. long l»y 3 wide at top. There are signs of minute lateral defensive spicules. The general form and struc- ture resemble those of the modern sponges of the genus Ifolnsrus.
I changed the generic name to Ci/dtliospoiK/id in my paper of 188!), as the termination 8eeme<l incon^ict; but this name seems to have been preoccupied by Prof. Hall. I therefore leave it in the original form until amended by the author.
The si)onge8 of the genus <'i/othophyrus are not abundant in t!ie
Sec. IV., 1896. 7.
no
UOYAL SOCIETY OF CANADA
beds cxploi-cd at Metis, and iiKtst of them have Ik-cii luudi lii'dken ii|». Only one speciinon was obtained in a toicniMe state of completeneHs.
For further rernai'ks on the strueture and affinili«'s of this sponge liv Dr. llitide, see tlie paper of 1S81>.
(Jenub ACANTHODICTYA. Himlr.
Kponj^es approximately siiheylindrieal in forni.jeoiisiHtinsj: of a skeletal mesh-work of loni^itudinal and transveiNe spieular strands or fibres. The lon<;iludinal strands are composed of somewhat loosely ari'anncfl fascieles of elongated overlappinff s])ieules. and I la; sj»i(ules (d' the slender trans- voi"so fibres are as a rule disposed in a siuifle series. From the outer surfaee of the sponge, numerous spicular rays ])rojoet outwards at I'iii'hl an«;les. The spony-e a]»pears to have been anchored by a basal prolony- ation of the longitudinal strands. Owin^ to the present c^)mpressed ecmdition of the s]>e(imens it is dittieult to determine the original form of the constituent spicules. Some of the elon<;ated Icmgitudinal spicules may be merely simj)le i-oddike forms, others are clearly cruciform and their transveree rays form the cro.ssfibres. The spicuiai- rays of the ])rojectinfr bristles of the surface may be the free distal rays of normal hexaetinellid spicules, but only these projecting rays can now be clparly distinguished ; the (jthers are merged in the longitudinal fascicles.
The general structure of the skeleton resembles that of Cijathophyous. Waleott, but it is characterized by the })resence of the projecting surface rays. The mesh is also of a looser character than in Cyathophycus and its arrangement in quadrate areas is only faintly i-ecognisable.
!». — AcANTHOniCTYA HISl'IDA, HiluJc.
(Figs. 20 and 21. PI. III., Fig. 11.)
21.—Acanthodictyn /u'sjatrffr.— Portions enlarged x showing frninework and cruciform and protective spicules.
o,
Fig. ^.—Acanthodictya hispida. Restored.
[DAWSON] FOSSIL STONGES AND OTHER ORGANIC REMAINS
111
The ('X!imi»lc's of lliis H|»ucit'8 wore pi-oluildy m-arlv i-yliiidrifiil tulios from :{(» to fjM mm. in loriiflli, iinil alioul 12 mm. in width. Tlu' longi- tudinal fascicles a !•(• alxtut 1 mm. iipart and tlu' transvcrsi' tiln-os from 1 to 2 mm, distant from <'a(di otlior. Tin- projectin<;- spiculai- rays (d' the surfaci'H are only seen in these t'ompre.st;'_,l jpon^^es at the lateral mari;ins a.s a sort (d' frinife. The five rays are somewliat thickly set ; they vary from 5 mm. to 3 mm. in lenifth ; the lon<j:er I'orms in some instances occur at re^'ular intervals, proiuihly at the angles of the mesh, and hetwi'en these are the shorter rays. The extrenuties of many t)f the larifer foi-ms jivo slif^htly swollen or cluh-Hhaped. Itut it is uncertain whetlior this is an oriu;inal featui'e or is due to an irreifidai- di'position of the pvrltos whi(di has now in all cases replaced the silica.
This species appears as i-ihhand-liUe hands composcil of vertical and parallel bundles of delicate spicules, with slender nansverse spicules crosBin;j; them at intervals like the rounds of a lad<ler. It was |)rohal)ly oi'i^inally cylindi'ical, hut the e.\t remit ii>s have not heeii seen, thouy;h frannicn's nearly three inches in length have ]»cen found. One of its most con.sj)ieuous eharactei-s is the possession of dense fringes of long protective sjjicules at the sides, and these seem to he hased on a cortical structure of crut(di-sha|)e(l or ci'uciform spicules, from which the defen- sive spicules spri g. Scattered cruciform spicules of snudl size upoear also in the middle of the i)an(ls. The fascicles of longitudinal spicules ui-e sometimes loosely twisted in a spiral numner. Ilinde suggests that in some of our sponges this appearance may he caused hy the accessory threads, indicated hy Schulze as Comitalia}
Sponges of the ahove species are sometimes associated with the larger masses of Protospongia in such manner as to suggest a parasitic or commen.sal relation ; hut this may he accidental, and may arise from the cortical s])icules of Aciint/iodicfi/it hecoming entangled with the sur- face of neiglihouring sponges. In one specimen 1 have the anchoring- rods of ProtdSpotK/id tctranniui. with a patch of pj'rite inclosing some of the spicules at the top and apparently attached to this, and rising from it a specimen of Acauthodictya. This siiecimen certainly appears to suggest a commensal relation. Another specimen is attached laterally to the side of a fragment of Protospontjia, and another is very long and much curved.
It is possihle that some of the spirally twisted anchoring-rods men- tioned helow may have helonged to this species, hut these have not V)een seen attached, and there are only faint indications of simple or loosely spiral roots.
The genus, no doulit, approaches to Cyathophycus, but is separated by its cylindrical form, tlie fascicled character of its longitudii al rods, and its cortical spicidar arrangements.
' Challenger Report, vol. xxi., page 17.
112
ROYAL SOCIETY OF CANADA
riENUS PAL.EOSACCUS Hindc. (London Geologicul Magazine, February. 1803.)
Cylintlrifal glolmlar or aac-like sponges, with thin walls of rhombic moslR's. The strands of the mesh-work consist of fascicles of slender rods, cruciform, and. perhaps, tivc-rayed spicules ; the interspaces are either open or covered with a thin layer of irregularly di8i)osed rods and cruci- foiT.i spicules. No anchoring spicules have been found in immediate connection with the sponge, but there are with it on the same surfaces elongated anchoring-spicules with ornamented spiral ridges which may belong to it.'
From Ci/dthojjhi/cns, Walcott. which appears to be nearest allied, this genus is distinguished by tho rhombic character and large size of the mesh-work ; the generally similar .structure both of the longitudinal and transverse strands of the mesh. an(i the greater development of rod-like spicules. The same features likewise differentiate it from Pkctodenna^ Hinde, and Phormoaella, Hinde,
10. — Pal^osaccus Dawsoni, Ilinde. (Figs. 22 and 23. PI. III., Fig. 9, PI. IV.)
Fig. 22.— Spiral anchorinK-rods, distal ends enlarged.
Fig. 23.— Portion of anchoring- rods, enlarged
Sponge of large size, apparently cylindrical in its complete form ; the part ])reserved consists of a flattened portion of the wall-surface more than a foot in diameter ; both the upper and the basal poi'tions of the sponge are wanting. The rhomliic meshes of the wall vary from 14 to 20 mm. in width, the average width is nearly 17 mm. The strands of the inesb mostly consist of very slender rod-like threads apparently simple, which are loosely an-anged. in strands of five or more, generally jtai-allel with each other. At the angles of the mesh there are. very frc(|uenlly. if not in all cases, stouter cruciform, or pcrlaips tive-rayed
' namwc^ ancient ; namntr, coarse cloth, sack, strainer.
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
113
spicules, and Hleiidor criUMlorm spicules are likewise intenninified witli the rods in the strands. In the iulerstiees of the mesli-work. and ap])areiitly exterior to it, there is, iu some portions of the sponge, a thin open layer, conipo.sed of slender rods and erucifonu and other spicules, overlappin<^ each other without definite arranifenient. It is ])rol)al)le that tiiis layer formed the outer surface of tiie sponge, for the spicules are of the .same character as those of the strands of the mesh.
The manner in which the small spicules seem to have drifted to one side, shows that they proliahly formed the cortical layer covering the whole surface, but became disengaged on decay of the soft parts.
Some uncertainty arises respecting the anchoring appendages of the sponge, sinee the basal portion is wanting, and no anchoring- spicules are found in immediate ctmtact with the specimen, but on the surface of the same rock-beds in which it occurs there are many pecu- liarly ornamented spiral roils which may belong to this sj)ecie8. They appear as if they consisted of several very minute filaments spirally twisted together, like the strands of a rope. Each filament has a row of projecting tubercles, which in the rod are definitely arranged in quin- cunx, so that the general ornamentation is very striking. At the distal end the rods are slightly curved, and the raised lines are more straight, and assume more the aspect of distinct filu-es. As with the other spicu es, these anchoring-rods are now of pyrites.
Later observatiims tend to connect these anchoring-rods almost cer- tainly with the present species. The rods are found almost exclusively on the same surfaces with this sponge. They do not appear to belong to any other form in these beds. Fragments of the base of the sponge show thai the strands of the framework have there an imperfect spiral arrangement, though slender, and if several of them coalesced at the base they would assume the form of the spii-al rods.
So far as can be at present determined this sponge appears to have consisted simply of a delicate thin sack or cylinder of spicular strands forming a rhombic mesh, with a thin outer spicular layer. There is no evidence that the sack inclosed an inner spicular tissue, and probably this thin wall repi'csents its entire skeleton. A similar condition seems to have been present in Protosjwiujia, Cyathyphyrus, and probably also in Dictyosponyia and the genera allied to it, but in none of these do we find the structure on such a large scale as in the present form.
114
KOYAL SOCIETY OF CANADA
Suborder ^foNACTiNELLrDA, or of (louhtf'ul affinity. Genus J.ASIOTHRIX, Iliiide.'
Sponyos small, depressed oval in outline, the outer surface covered by a layer of loniritudinally ari-anifod, apparently simple, aecratc spicules ; beneath this is another layer of spicules disposed transversely. From the hasc of the sponnv several simple elono-ated spicules extend.
The pecidiar ari'anu;ement of the surface s])icules in this form indi- cates a probably nt'W i;enus, but in its present condition one cannot tell with certainty whether it is monactinellid or hexactinellid. The outer surface seems to have been invested with a sheathini;- of rcii-ularls ar- ranu'ed acerate spicules, and beneath these other spicules, disposed trans- versely, can be tlistin«fuished. but whether these are really acerate or modified hexactinellid spicules there is no decisive cvideiu-e to show. In one or two instances the s])icules appear to be crucifoi-m, and the presence of the lonir, simple anchorinii;-siticules extendinii; from the base of tlu' sponuje, ])recisely as in normal hexactinellids. is a further point in favour of its belonii'inii' to this division.
11. — Lasiothkix cukvicostata, Jlindc.
(Fig. 24.)
The type form is t ransvei'sely oval. S mm. in height by 12 mm. in width, the anchoring-spicules can be traced to a length of 15 mm. from the body. The summit is rounded. There are some nodular elevations of pyi'ites in tlu' body portion, but it is doubtful whether they represent
Fid. '24.~ LasiothrU' ciirricosfiitd. Natural fsize and i)ortioii eiiJarKt'tl.
jiggregations of spicules oi- are merely due to the chemical deposition of the mineral, in connection with the presence of organic niattei'.
This curious little sponge, of whi(di few sj)ecimens were found, is remai'kable for the strong curved spicules which support its sidcis. giving
I British Fossil Sponges. Pal. Soc, 18.S8, PI. i., lig. a.
[DAWSON] FOSSIL SPONCiES AND OTHER ORGANIC REMAINS
115
the appearaiite ot" a rounded haskct with strong vertical ribs and very slendor horizontal bars, within whitli and at top were quantities of slender straiii'lit spiculehi.
12. — Lasiothkix klabellata, s. n. (Fig. 25.)
Fi<i. •2h.—L<tfiio(li ri.r jUihellata. Restored, and .spieulo.s x 5.
I have some doubt as to the rin-ht of this species to be placed in Dr. Ilinde's new genus; but the specimens much resemble the former species, and may accompany it provisionally. The surtace appears to be covered with small ovoid bundles of stout biacerate s])icules, diverging from the centre and sometimes in fan-shaped tufts. Tlie specimens show indications of an external meml)rane, and they had somewhat strong root spicules, much larger than those of the body. It seems uncertain whether the fan- shaped bundles are really such or flattened groups of radiating sj)icules surrounding small oscula. In some specimens the spicules arc confusedly scattered in tilms of pyritous matter with little indicati(m ot radiating arrangement. Di-. llinde remarks as to this form that •' the spicules do not stand out detinitely. as in the case of the hexactinellid sponge spicules, but appeal- to be imbedded in some membrane. In two instances, aiudior- ingspicules, like those of Trotospimgia, project from the base of the mass. I do not know of any monactinellid sponge lurnished, as these appear to have been, with long anchoring-spicules."
The sponges of this genus are very rare in the Metis collections, and are obscure and ditticult to make out as to their details.
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ROYAL SOCIETY OF CANADA
Genus nALlCHONDRlTKS. Dn.
13. — Ualichondritks confusus, DawsDii.
(Fig. 2(J.)
Fig. 26.—Halichondrifes confuatis. Spicules enlarged.
Oval or irveo-uliiv masses of small simple spicules, imbedded in patches of pyrite, and without any definite arnin<);ement of ivot spicules, may indicate tlie presence of a halichondroid sjionge. In the best preserved specimens the spicules appear to be biacerate and more slender and pointed than in the last, and they seem to be in two series, inclined at a very oblique angle to each other. In some specimens elongated spaces, with well-defined margins, are covered with thin films of pyrites, which may have i-esulted from tlie rei)lacement or incrustation of a mass of minute spicules, of which traces remain in some places.
It is to be «)bservcd in this connection that sponges having originally much keratose or other dense animal matter would naturally aggregate in and around themselves a greater quantity of pyrite than those of a more purely siliceous character.
Genus STEPHANELLA, Hinde. Established by Dr. Hinde, London Geological Magazine, 1891, p. 22, to contain some sponge remains discovered by Dr. Ami in the Utica shale at Ottawa, and consisting ai)parently of groups of very fine radiating spicules. *S'. sancta, Ilinde, is the type species. Dr. Hinde regards them as basal spicules of a sponge to which other outer structures which have perished may have been attached.
14. — StEPHANELLA HINDU, s. n.
(Figs. 27, 28 and 29.)
Fig. in.—Stephanella IlindU. Slightly eiiliirgcd.
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
117
Many tViiifineiits t»l' this species have l)oen ibund from time to time, bliowiiii;' ionjf stout taporiiii; anchorinjij-rods with masses of long slender simple spicuk's near them ; hut in 18!t5 for the first time nearly perfect specimens were ohscrvcd. They consist of discs somewhat lari^er than tho!J« of S. satirt((. made up of fine straight spicules radiating from a intint near one side and i-ather coai-ser tluin those of S. sancta, and showing here and there a tendency to he aggregated more densely as if in hundles, Itut this is not very marked. At and toward the circumference there are occasionally a few very snndl cruciform spicules which, as they are not confined to one specimen, I regard as prohahly the remains of an outer or cortical layer. If they are accidental tliey must he the smaller spicules of disintegrated Protospongia^ entangled in the spicular surface of Ste- phanella. It seems more likely, however, that they are a i)art of its structure, in which case it furnishes an example of a sponge with a dense internal skeleton of radiating spicules. Fig. 27 represents a nearly
iSlk^'
Fi(». 2S.—StephaneUa Hindii. Fragment Fi(i. '29.—StephaneUa ? Anchoring- with anchoring-rods. rods and part of the spicules, enlarged.
complete specimen, and Figs. 28 and 29 disintegrated fragments with the anchoring-roots, whi(d\ in some specimens are longer and more tapering than in others, though always very stout at the hase.
In Dr. Ami's specimens from Ottawa, a few stout anehoring-rods and cruciform spicules are found in the same dahs with Stei^hanella, hut none of them are seen to he attached. I think it not improhable, how- over, that the former, at least, belong to Stephanella.
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ROYAL SOCIETY OF CANADA
IN('P:ilTiE SEDIS.
15. NoN-8i'i('i;i,ATK si'ONUEs. — Pyritoiisspots of iiidctcriniiiiile form, iiiicl showiiii; iiiulcr tlio Ions only an oliscnre <i,Tannhir and Hoctuleiit ap- ]»earanc'o arr not infreciuont on the. surfaces of the Metis shales. In addition to these, howevei'. tiiero are two types of these oltjeets of more detinite sliape. either triaiiii'nlar with a (hirk space in the centro or oval. The former seem to lio flattened liollow cones, the latter possihiy flattened sacs. Someof the former show suiticieiit traces of spicules to connect them with Protospo/K/id riiathiformix. while others may he entirely pyritized individuals of P. (It'lhufuhi. In aihlition to these, however, there are others which, under the lens and when moistened, show indications of simple linear spicules, and more numerous examples which seem to be composed of indeterminate and interlaced fihres remindincj one of the tissue of a c()i-neo\is spono-e. None of them have any indications of aiudiorini; rods. For the present I merely mention them as possihiy indicatinj^ types of sponi>-es distinct from any of those ahove described.
lli. Spiculate sacs. — Imbeddcil in the debris of the larg-er specimens of Hyalostelia, there are oval flattened patches made uj) of a dense mass ot' very snudl and apparently sim])le spicules, but presenting mi a])erture or anchorini>--rods. lliivinii- found them only in connection with Hyalo- stelia, I at tirst inuii;;ined they might be -some form of ovarian body ; but Dr. T'^'v\<le doubts this, and is inclined to regard them as distinct organisu. One of them is represented in Fig. 30 of about the natural
.>f:
Fk;. 'M.—Spirul(ife sac, found with tiyalostelin.
si/c. If distinct .sponges, there uuiy have been some commensal relation iietwcon them and Hyalostelia. They are quite distinct from the little masses of broken spicules referred to above in Section IV.
17. Minute Globular or Circular Bodies.
Surfaces of an inch or more in diameter are occjisionally sli])pled with mimite pyritous spots ; when magnified these appear perfectly round and of approximately uniform dimensions. The}' may either be inor-
[DAWSON] FOSSIL SPONGES AND OTHER ORGANIC REMAINS
119
<;;imi(' discs oi' pyrite. or may ropi-esent flattened »)ru;anic bodies. In the liitloi- rase, they may l)e ii;eiMns or ova. or s])()res, or portions of some foniplox \'Oif«'tabie or animal ori^-anism Tlioy recall the little spherules described by Matthew as occurrimr in the Cambrian of Xew Brunswick, and named by him Monddifrs (//i)l)u/(iris. I have not been able, liowever, to detect any indications of coiniectinii- rods or stalks like those figured bv Matthew.'
Vr. OTHER ANIMAL EEMA1N8.
The most important of these are the little brachiopods referred to above :
Obolella (Linnakssonia) pketiosa, Billinifs.
"b c
Fi(i. '.i\.—TAiinarssonia prei iosa, Billings, a, natural size of medium specimens,
6, ventral, c, dorsal valvf.
These are very alnmdant on tlie same surfaces which hold the sponges, and are usually replaced by pyrite. though sometimes appearing as mere casts. They often show their interior structures as represented in Fig. 31. They afford for the present the best evidence in relation to the geo- logical age of the deposit, since the species is characteristic of the Sillerv,and the genus is a Cambi-ian rather than Ordovician one in Europe. For this reason I ([Uote here Dr. Hall's description, based on Metis specimens submitted to him some years ago. I may add that Mr. Whiteaves. our best Canadian authority, concurs in referring these shells to Billings's species 0. pretinm :
■• Shell smail.subcircularorelongate transversely. Valves subeqmdiy convex, the ventral beak ei-ect. slightly projecting and perforated at its apex. Externa) surface covered with fine concentric lines, faint radia- ting .stria^ being visiiile on the interstitial lamelhe. Tiie interior of the ventral valve bears a subtriangular or U-'^l'^'P^'l ridge, the branches of which diverge anteriorly. The thickest portion of this ridge at the union of the branches is penetrated by the foraminal lube. In front of the foramen, and just within the cardinal line, on either side the axis of the shell is a conspicuous tubercle or boss. In the dorsal valve is a median ridge, extending half the length of the valve, and from this two short lateral ridges diverge, taking their origin at one-third the length of the median ridge from the posterior margin."
Transactions Royal Society, 1889.
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ROYAL SOCIETY OF CANADA
ANNELIDS.
Trails and caKtiiii^s of woi-ms arc not infrequent in tlie shales holding the sponges. Some surfaces are covered with what seem to he very minute eylindrical smooth trails of worms, aii<l larger worm-like Ixxlies in pyrite seem to represent casts of harrows or of the hodies of worms. Some of these are a quarter of an inch in diameter and rudely annulated in an irregular manner. There are also a few casts in pyrite of spiral forms like the Aroiiccolitcs sj>inUit<. already mentioned. These hurrows and trails are similar to those found in various places at and near Little Metis in the heds of the Quehec Grouj).
MISCELLANEOUS FKAGMENTS.
Minute fragn>ents, possihiy referable to Trilohites, Cystideans and (rraptolites, ai'O occasional!}- seen, though very rarely, and are quite indeterminable.
AUiJE.
BUTHOTREPHIS PERORACtLIS, DaWSOU.
(Fig. 32.)
Fig. 'S2.—Bufhofrephis pergracilis.
I have nothing to add to the description of this species in the paper of 1889, except that some ot the specimens appear to be connected below with a network of slender filaments spread out on the shale, that some of the specimens show indications of a structure of elongated cells or fibresi and that at the extremities of some of the branches there are tufts of rounded masses of granular pyritous matter ; but whether these are
\li
[dawbon] fossil SPONdES AND OTHER ORGANIC REMAINS
121
roiriiiins of ortciviis <»t' tViictificiitioii or attached animal structures, or merely inorganic ai^iircifations, 1 luive not been al)lc to determine.
ClIONDORITES MeTISSICUS. 8. n.
Flattened fronds, two to four millimetres broad and the largest eight to ten centimetres long. They are riband-like and smooth, with even edges and fork dichotomously at angles of 40° or more. They show traces of carbonaceous matter but no structure.
In concluding this paper I think it proper to remark on the exuberance of sponge life, both in abundance of individuals and of generic and specific forms on a limited ai^ea of muddy sea-bottom of the lower Ordovician or later Cambrian age, evidenced by the collections made at Little Metis, the account of which in this paper is presented as merely the result of recre- ative excursions in the summer vacation, in a field ditferont from that in which the author is usually engaged.
In a formation usually little productive of fossils, and in muddy depo.- ts, which must have been laid down in water at a low temperature and in the intervals of conditions producing beds of a coarse mechanical character, this abundance of delicate organisms is very unexpected and surjirising. We have to observe also that if the sponges in question were, like their modern allies, inhabitants of deep water, there must have been considerable oscillations of'level at the time when they lived, as well as much deposition of earthy mattei-s in circumstances unfavorable to marine life, as evidenced in the great thicknesses of barren material inter- vening between the sponge-bearing layers.
Dr. Hinde has already mentioned the close alliance of many of these Palu'ozoic «])onges with their successors in later formations and in the modern seas, evidencing the great permanence of the siliceous sponges throughout geological time, and the fixation of the mechanical and vital laws of their structure and growth at a very remote period. More especially is this remarkable if we include with them the spicular forms which have been recognized in the Laurentian, Hui'onian and Early Cambrian rocks. The graptolites belonging to the oceanic waters of the Cambrian and Ordovician have already indicated the paramount im- portance of giving attention to the general oceanic fauna of these periods, as well as to that of the continental plateaus, and it is possible that in future the sponges may also ]»rove of more value than heretolore in regard to questions of relative geological age.
The results of these observations at Little Metis, in connection with the obscure and unobtrusive character of the fossils, also show how much is in the power of local collectors, having time and opportunity to follow up any discovery by excavation and continued collection. In this way beds for the most part unfossiliferous and presenting few attractions to a passing collector, may be made to yield unexpected scientific treasures.
•1
[imwson]
FOSSIL SI'ON(JES
Tras.s. 18!MI. Skc. IV.— Pi atk I.
I'k;. I.
Fk;. 4.
Fig. X.—l'foliinpoiKjia fitriiiit'iiKi.
Fig. 2.— P. inononi'tnn.
Fig. 3.— Do Showing ()S('»/i'))(, partly broken away.
Fig. 4.— P. (etranenia. Seen in section with root. (Ail natural .size.)
123
[DAWSON ]
FOSSIL SPON(iES Trass. 1896. Sec. IV.— Platb II-
Fk;. 5.
Fui. 0.
Fk;.
Fiu. «.
Fig. f). — Cru.shed specimen of Protosjjtini/iu corunntu, fiicnisliMl with pyrite. (Natural size.)
Fig. 0.— ymiiiltT perfect specimen of tlie same. (Natural size.) Fig. 7.-7'. cy((fliifurniis. (Nulural size.) Fig. 8.— Tlie same. Youug specimen enlarged.
12B
[dawsox]
FOSSIL SPONGES T.jans. ISlKJ. Sec IV.— Plate. III.
I'll:. 11.
Imc. il.
Fill. 10.
1"
h
l"'in'. !t. I'orl.ioii ()(■ /'ii/ii iifiiiiciis Diiirsiini.
Fi.u;. Id. Siiih with sniali spei'iiiu'ii of llynlosliiiit Mflissicii iit (u). /'nifos/iinKjid cjiatlii f'untiis iii (Iji iiiul fraKiiii'iil nl ('jiiithiipliyvas a\. (c).
Fig. ll. — Actiut/iixlicti/d liisiiiiln. Frajimt'iit of small speciiuen. partly encrusted with pyrite. Fig. 12.— Debris of Prutuspuiiyia. (All luituriil size.)
127
^
fl^i
[pawson]
FOSSIL SPONGES Trans. 18<JG. !jkc. IV.— Plate IV.
Fi(i. i:{. Fig. 13. —Spiral anchoriug-rods of Ptduosaceuti, enlaiged.
ISO