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Les diagrammes suivants illustrent la mAthode. by errata ned to tent une pelure, fapon A 1 2 3 32X 1 2 3 4 5 6 Section IV, 1889, [ 31 ] Trans. Eoy. Soc. Canada. Ill, — On New Species of Fossil Sponges from the Siluro-Canibrian at Little Metis on the lower St. Lawrence. By Sir J. "William Dawson, LL.D., F.R.S., &c. (Including Notes on the Specimens, by Dr, Gr, J. Hinde, F.Gr.S.) [Plate III.] (Presented May 7, 1889.) The specimens described in the following paper show the existence of a rich fauna of siliceous sponges, more especially of the genus Protospongia of Salter, on the muddy sea boctoras of the Siluro-Carabrian period, and in that early portion of this period repre- sented by the Quebec series of Logan, and probably by the Levis division of the group. ' They are also remarkable as illustrating the structures and habit of these ancient forms and the manner of their preservation. The beds at Little Metis have hitherto been very unproductive of fossils, but in the summer of 188*7, Dr. B. J. Harviugtou, F.G-.S., was so fortunate as to tind a bed of black shale rich in remains of sponges, hitherto unknown in these rocks, and having made known the fact to the writer, we visited the place several times and made collections of these interesting fossils, which are now in the Peter Redpath Museum. Subsequently, iu the summer of 1888, more extensive excavations were made in the reefs of shale ex- posed at low tide, and it was found that the deposits of fossil sponges are limited, so far as could then be observed, to two thin bands, each of them scarcely more than two inches in thickness, in the black shales near the head of Little Metis Bay. From these bands, by carefully tracing them along the coast and excavating where the exposures were suffi- ciently good, a large quantity of material was obtained. This was first carefully w rked over by the writer and subsequently submitted to Dr. Gr. J. Hinde, F.Gr.S , of London, whose results are embodied in the descriptions of the species in the present paper. Later exploration showed that the-'e are remains of spong-es in other beds ranging through a vertical thickness of about forty feet of the shales ; but not so abundantly as in the layers previously explored. Little Mi'tis Bay presents a good section of rocks of the Quebec group, including sandstones, slates and conglomerates similar to those which characterise this series of beds along the south shore of the St. Lawrence. The distribution of these beds is shown in the accompanying map,^ from which it will be seen that the general dips are to the south-eastward, and that there appear to be lour bands of sandstone and conglomerate sepa- rated from each other by intervening shales, often of dark colours and carbonaceous, but sometimes lolomitic, and in many places showing gray and red colours. Assuming the series from the Lighthouse Point to he an ascending one, the thickness of beds exposed at the head of th«' l)ay would be iiion* than !],00() feet ; l)ut it is not improbable that ' I.(i>.'iiii, (iooliiL'.v of Ciiiiaiia, 18(;3; Selwyii, Ucjiort (u'ol. Survey, 1S77-78; KIIh, Ihhl., 3880-81.'; l,a|W()rlli, ( 'aiiailiaii < ira|ptoliteH, Trans, Hoy. .Soc. Can., iSfSd. ■ For tlio t't'ograiiliical part of tlip miip on tlie following pago I am indel>ted to l>r. Ells of the Geological Survey. 32 DAWSON AND IIINDE there may be repetitions by faults or folding. The &. ndstones and shales of Lighthouse Point contain Retiolites ensifwmis' of Hall, many trails of worms, and worm castings of the type of ArenicolUes spiralis. The sandstones of Mount Misery contain fragments of Retioliles ensiformis. The shales on the south side of the bay, presumably near the upper part of the series exposed, contain the sponges in question, a species of Linnarssonia not distinguishable externally from Obolella pretiosa of Billings, and the slender branching fucoid which I have described as Bnthotrqjhis pergracilis. " f*'" .1*'' ^"^ RIVER s^LAV..^tNeE: funcfs/orw ^Crmafomerale ■Ifia/e Sketch map of Little Metis Bay ami vicinity, showing locality of Fossil Sponges. (Scale about 2 inches to a mile.) KoTK.— The scries from tlie Olmreh to Mt. Misery is probably despending and conformablo; but the siindstonps forming the cliff near McNider's Brook to the eastward, arc not improbably those of Jft. Misery thrown to the southward by a fault, and not ns would appear from the map a continuation of tliose near the Church, which probably pas.- inland of Ihcni. In the conglomerates are limt^stoue boulders, holding fragments of Trilobites of the genixs Solenople/ini and otlier fossils ; but these seem to be of Lower Cambrian age, or considerably older than the beds in which they occur. There can be no doubt, from the stratigraphical position of these beds, that they belong to the Quebec group of Sir W. E. Logan. This is, however, now known to include, on the Lower L>t. Lawrence, beds ranging from the Calciferous (Tremadoc) to the Trenton (Bala), and the beds are so much plicated that it is often dilhcvxlt to unravel their complexities of arrangement. At Metis, the evidence of the pebbles in the conglomerates iudicat 's that they are newer than the I^ower Cambrian, and the few fossils found in the sandstones and shales would tend to place them at or near the base of the Levis division, or approximately on the horizon of the Chazy, equivalent to the linglish Arenig. Lapworth, in his paper on " Canadian Graptolites," ' suggests that the sandstones holding Retiolites may be older than this ; but hitherto we have not found at Metis the charac- ' Identilied hy Lapworth. ' Trans. Roy. Soc. Can., 1880. '' Notes on Specimens in the Tetor Hedpath Museum, IxsS. ON FOSSIL SPONGES FROM METIS. 33 teristic Graptolites of the older or Matane series, which occurs further east, and is I)robably of Calciferous or Tremadoc age. The locality of the fossil sponges to be described, is the beach at the foot of the clifF iu front of the Wesleyau church, on the south side of the bay, where a considerable thickness of black and gray shales is exposed, forming low ledges extending along the beach parallel with the direction of the coast. The dip is S. 10' W. (magn. var. 22° 33' W.) at angles of 45° to 50°, and the bods containing the sponges are best seen opposite a huge boulder of conglomerate on the beach, and about 00 feet from the face of the cliff. The sponges were first discovered in a thin layer of tough black shale having hard gray and soft black beds associated with it. A second similar layer was afterwards found about nine feet outside the first and therefore underlying- it, besides other beds holding frag- mentary remains (see section below). Both these layers have Linnarssouia and Bathotrephis pergracifis associated with the sponge-remains. The following is a general section of the beds in descending order : — (1.) A thick bed of hard sandstone or quartzite and conglomerate, underlaid by coarse gray arenaceous shales, and forming the clitf immediately in front of the church. It shows in some of the beds radiating markings (Astropolithon). (2.) Black and gray shales, the former thinly laminated and of fine texture, the latter harder and arenaceous, with some hard calcareous or dolomitic bands — thickness about 100 feet. The black shales of this division hold sponges and layers of sponge spicules, especially in the two bands above referred to, with fucoids {Bathotrephis) and valves of Lin narssonia. All of those fossils are usually in a pyritised state. (3.) I'laggy sandstone and shale, gray and dark-colored, about twenty feet. (4.) Hard gray sandstone with quartz veins, three to five feet. (5.) Hard gray shales and calcareous and dolomitic bands, with some layers of sand- stone — 800 foet or more. (0.) Api^arontly underlying these, and occupying a great extent of the shore, are l)lack, gray and red shales and thick beds of gray sandstone, the latter appearing- at Mount Misery and Lighthouse Point, and holding the Graptolites above referred to. These beds must be of great thickness in the aggregate, but they are possibly repeated in part by faults and contortions. Along this coast the beds generally run approximately parallel to the shore, or slightly oblique to it, with south-easterly dip, but at intervals they are broken by trans- verse fractures throwing the beds, locally, into different lines of strike, and often accom- panied by violent contortions of the strata. Beyond these they resume their usual course, so that the outcrops form a series of salient and reentering angles along the coast. At the south side of Little Metis Bay there is a comparatively undisturbed portion, extend- ing for more than half a mile along the coast, but there is one break, throwing the beds nearly at right angles to their former position, at the mouth of Little Metis Eiver, in the head of the bay, and another to the eastward near Turriff's Hotel, where the beds, as seen on the beach, are much contorted. Beyond these breaks, beds similar to those holding the sponge-remains appear to the westward at Grand Metis Bay, and similar beds appear with like accompaniments near Bic To the eastward they appear at several places on the coast, and have allbrded graptolites of Levis and calciferous age. ' 'Beportof Peter Reilpatli Museum, no. ii; l-apwortli, C.'iiiinilian lirnptolik'S. Soc. iv, 188S). 6. 84 DAWSON AND HTNDE The following is a moro detailed section of part of the second division above, in descending order, measured on the surface of the outcrop : — INCH Black shale 8 Dolomitio band (weathering j'ellow) 3\ Gray ami black shales 12 Doloniitic band 1 Black shale Gray and black shales 15 lilaek shale 8 Gray and black shales 30 Black /hall' (sponges, &c.) 3 I sen. Black and gray shales, with remains of8iM)nges in some layers 72 1 )o!oniitic band 2 IMack and gray siiales 34 Doloniitic band. 3 Black and gray shales :>(> Black and gray uliaks (spunges, &c.) Black and gray shaIos,witl: thin, interrupted dolo- niitic layers as before, to base of the division. A third sponge-layer was found in the lower beds, about 30 feet vertically, or 50 feet measured on the shore, below the last dolomitio band. The sponges contained in the layers mentioned above, are apparently confined to a small thickness of the shale, but in this are quite abundant. They are perfectly llattened, and -aeir spicules are replaced by pyrite ; but in some cases they retain the outline of their form, and have their root spicules attached. The spicules were, no doubt, originally siliceous, but they have shared the chemical change exvorieuced by other fossils in this bed, whereby they have lost their siliceous matter and have had pyrite deposited in its place. In some cases, also, the pyritised spicules ■ave been frosted with minute crystals of the same substance, greatly enlarging f r ze and giving them a mossy appearance. This pyritisation ol spicules, once probac'^; siliceous, is not uncommon in Palceozoic rocks, and it arit. >s from the soluble condition of the silica in sponges, and its association with organic matter, which, in some modern sponges, as in Hyalouema, enters into the comjiosition of the spicule itself. These s; ' 'ules, therefore, suffer the same change with the calcareous shells associnted with them. Many of the sponges in these beds were entire when entombed. Others are decayed and partially broken up, and there are some surfaces covi'red with confused patches of loose spicules arising from the disintegration of many specimens. Some remarks are perhaps nec^essary here respecting the appearance of sponges in different states of preservation. Of t;ourse the original textures of sponges are difl'eren^ and those which have consolidated spicules or firm external cortex, are those most likely to retain their original forms. Even the looser kinds of sponges, however, may under certain circumstances, preserve thi'ir rotundity of form. In this case they usually show external markings, but not so well internal structure, unless when sliced. On the other hand when completely flattened, which is usually the case in shaly beds, only an out- line of the general shape remains, and sometimes not even this, while the forms and in part tli(» arrangement of the spicules are usually apparent. Farther, the hollow and thin-walled species are more liable to be I'ompletely llatteii"^ thouyu ;:i some cases, as in the Devonian Dictyospongia?, they may retain their form. It was this property, and the membranous appearance of the outer coat, that for a long time sustainett the belief that these last were plants rather than sponges. In the case of the sponges procured in the shales at Little Metis, perfect llatteuiug has occurred, and in many cases the spicules have been separated, and appear as meve ON FOSSIL SPONGES FilOM METIS. 86 IN en. es .. 72 .. 2 .. 34 .. 3 spicular patchos or layers. In othor iustuuci's, however, Ihoy rouiaiu approximately in their natural position, aiul even the gent^ral outline of the form eau be observed. The 'ollowing additional remarks as to the state of pri'servation and characters of the specimens are from notes made by Dr. Gr. J. Hindc, F.G.^. : — " Th(! Metis specimens are specially interesting, since they throw much fresh light on the character of the earliest known forms of these organisms, and their discovery is the more opportune from the fact that our knowledge of the existing hexactinellid sponges — the group to which all, or nearly all, these fossils btdong — has been vastly increased by the work of Prof F. E. Schulze, of Berlin, on the hexactinelled sponges dredged up by the Challenger Expedition, and thus w*' are now better enabled than hitherto to compare the fossil and the recent forms. " In the present specimens, the amorphous or sohxbh^ silica, of which th(;ir spicular skeletons were originally composed, has entirely disappeared, and the spicules now con- sist of iron pyrites. This replacement by pyrites is of common occurrejice, more parti- cularly in a matrix of black shales ; for example, the earliest known sponge, Protospongia fenestrata, Salter, from the Cambrian rocks of South Wales, is in tht; same mineral condi- tion, and in a nearly similar matrix, as the specimens from the Quebec group and the Utica shale. When thus replaced, the general outline of the larger spicules is fairly distinct, but where the spicules are minute, and in close proximity to each other, their individual oiTtlines are blur-ed by the tendency of the crystals of the replacing pyrites to amalgamate together so as to form a continuous film of the mineral in which the finer spicular structures are quite indistinguishable. This coalescenct* of the pyrites likewise makes it very difficult to determine whether the spicular elements of the sponge were organically soldered together into a siliceous mesh, or whether they were merely held in their natural positions by the soft animal structures, and owe their present union to subsequent fossilisation. " Next to the chemical changes, we have to take iato account those produced on the original structures of these spo:^ges by what may b< termed the mechanical influences of fossilisation. Thew can be no doubt that they were hollow sacci-form or vasi-form sirut^tures with very delicate walls of spicular tissue, supporting the soft animal mem- branes. They existed at tli(» surfact^ of the soft oozi' of the sea-bottom, and their basal portions were probably embedded in it. They were furnished with elongated spicules whose extension into the mud served to anchor them in one spot. After the death of the aniinal, and the d»'cay of the soft tissues, the delicate skeletal framework would be grad- jially biiried in the arcumulating sediments, until by their weight it became completely llatteni'd. Under favorable cinmaistances, the outline of the sponge and the natural arrangement of the spicular skeleton would be preserved, and this is fortunately the case with the specimens of Cyathophycus from the Utica shale, and with some of the speci- mens of Protospongia from Metis. More frequently, however, probably owing to currents and other causes acting at the surface of the ooze, the skeletal framework is partially or wholly broken up, so that only small patchi's of the connected skeleton, or merely the dislo.ated and detai'hed spicules irregularly scattered over the rock surfiice, renifiin for determination, and this is the present condition of the majority of the specimens from the Quebec group. For some reason, probably connected with the arenaceous charact(^r of the rock in which they occur, the nearly allied sponges belonging to the Devonian genus 36 DAWSON AND HINDE Dietyophytmi, Hall, usually retain their outer forms complete — that is, without being compressed — but most of these sponges exhibit only internal casts of their spieular skeleton, so that at present we know very little of their original structures. " As already mentioned, nearly all these Quebec sponges belong to the suborder of the Hexactinellidee, in which the fundamental type or elementary spicule of the skeleton consists of six equal rays, radiating from a common centre at right angles to each other, forming three equal axes. But this typical form is subjec^t to great modifications through the unequal development or even suppression of one or more of the individual rays, so that spicules with live, four, three, or merely two rays only, are frequently present, and in the same species of sponge several modified forms of spicules may be found. Now, in the compressed condition in which the Quebec sponges occur, we can, as a rule, only perceive those rays of the spicules which lie in the exposed plane of the rock ; these are generally the four transverse rays of the normal spicule, but the two rays forming the axis at right angles to the transverse rays, are not likely to be distinguished, for one would be concealed in the matrix immediately beneath the transverse rays, whilst the other, projecting above the exposed surface, would inevitably be broken away. Conse- quently it is very difficult to determine positively whether the forms with four transverse rays exposed on the plane of the spougc-wall, represent the entire spicule — in whitsh case it would be termed cruciform, — or whether one or both of the other rays of the normal spicules were originally preseit. Judging by the analogy of allied recent forms, it is probable thftt in most cases these spicules were furnished with a fifth ruy at right angles to the other four. In the examples of Cyathophycus from the Utica shale, are distinct traces of a fifth ray in some of the larger spicixles, and it <^an also be seen in detached spicules from the Qiiebec group. " In both recent and fossil hexactiuellids, many of the elongated filiform ant'horing spicules terminate distinctly in four short recurved rays, and are thus five-rayed spicules in which one ray is greatly developed ; but in other instances they have simple blunt or pointed ends, and may thus represent only one ray or one axis of the normal spicule. With the exception of two species, all the anchoring spicules present in the Quebec sponges seem to be merely i>ointed at their distal ends. In one species they are complex, consisting of several filaments twisted spirally. " In recent hexactin«illid sponges, in addition to the; spicules forming the regular framework of the skeleton,- then^ are much smaller spicules of varied forms, imbedded in the soft tissue's. These, generally known as llcsh-sjucules, are very seldom met with in the fossil condition, but it is not improbable that the delicate film of pyrites, seen in places on the surface of the Quebec sponges, may arise from the replacement of the flesh- spicules b "^ this mineral." The species of sponges noticed below have been submitted to Dr. Hinde, author of the British Mnseum, " Catalogue of Fossil Sponges," and the following descriptions are largely based on his notes on the specimens. The magnified tracings of the structures in the text have usually been drawn under the camera to one scale (about five times the natural size). The restorations arc based on comparison of the more perfect specimens, sopie of which are represented from photographs in Plate III. It is to be observed that the smaller cruciform spicules, though usually displacc^d, were in the living animals symmetricvally arrang'cd in the meshes. These smaller ON FOSSIL SPONGES FROM METIS. 37 spicules fonn secondary and tertiary structures within the larger areas formed by the primary spieules. Genus PROTOSPONGIA, Sailer. 1. — Protosponoia tetranema, S.N.' (Figs. 1 to 4. PI. Ill, figs. 1, 2.) Mm Fid. 1. — PrutOKpongia lelranema. A small si)ecimen restored. Fui. 2. — Prolofpongia lelranema. Anchoring spicules slightly enlarged In the specimens in which the outline of the sponge has been pr- ■ od, the body appears to have been elongated oval or rounded, measuring about 4;' in length by 80 mm. in width. There was an aperture at the summit, though it canii now be dis- tinguished, except in a few rare instances. The wall of the sponge app*'ars to have Via. 'X—ProtOKimngia lelranema. Primary, secondary and tt'rtiary cruciform spicules, x 5. 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 framework with quadi ite or oblono- inter- ' The I'haracters of this and soveral of the following sjiecies were given in " Notes on Sjiecimen.s in the Peter Uodpatli Museum, 1888." 38 DAWSON AND IIINDE spaces. The rays of the larger spicules couHtitutc the boundaries of thi^ larger squares, and within these, secondary and smaller squures are marked out by smaller spicules. Judging by the length of the rays of the larger spi(;ules, the larger squares would be about 5 mm, in diameter, whilst the smallest do not exceed 1 mm. The rays of the individual spicules slightly overlap, and it is probable that they may have been lightly «;emented by silica at th(^ points of contact. The rays of the larger spitniles are conical, gradually tapering from the central node to the pointed extremity ; whilst the rays of the smaller spicuh'S appear to be nearly cylindrical. For the purposes of this paper the different orders of spicules, in these sponges, may be designated as primary, secondary and tertiary spicules. From the base of the sponge, four slender elongated filiform spicules project. They are approximately cylindrical, pointed at both ends, from 0.1 to 0.25 mm. in thickness, and from 50 to 70 mm. in length. Their proximal ends are inserted apparently in the basal #^^^, V2^' " >*^Vy-v. ■^y>\ Fin. 4. — Protonponrjia telrariemn (?). Oscnlum enlarged, iind surrounded by minute spicules. part only of the sponge, and thi^y project in the same direc.'tion, though not in lateral apposition with each other. In perfect specimens their distal faids converge and unite terminally. The root spicules in the larger specimens aw about cm. in length. This sp(Mies is one of the most abundant at Metis. In some spei'imens the spicular framework of the body of the sponge retains in pla< 's its natural arrangement ; in others the framework has been almost entirely brokcsn up, and the constituent spicules irregularly mingled and compressed together. But in every complete specimen there are four anchoring spicules occupying the same relativii position to the framework or body- wall of th(! sponge, thus clearly showing that tliey arc essential to the species. In the spicules of the body-wall only four transverse rays cau be distinguished, but it is quite possible, as already mentioned, that a fifth ray may have been present. On out^ of the rock-slabs there is a di-tached spicule in which the fragmentary stump of a fifth ray can be clearly seen proji'cting from the central node of the transverse rays. The rays in this spicule are unusually long. There can be no hesitation in placing this form in the genus Proiosporiii'iu, since the same arrangement of the spicular mesh-work is present in it as in the type of this genus. In no other examples of the genus, however, has the presence of anchoring spicules been ON FOSSIL SPONGRS FROM METIS. 30 rncoguist'd, owing, no doubt, to tht'ir imperl'ect stiitc of prcsorvatiou, and this lonturi' may now b« rt'»;kont'd as ono of the geuorii! characters. In the present species, however, these anchoring spicuh's were very peculiar, and seem to have consisted of a cruciform spicule of which the rays were bent upward and lengthened, forming a stalk for the spouge. This would give a tirm attachment, and adapt itself to the gradual rise of the bottom to which the sponge was attached. The mechanical properties of such an arran- gement of spicula are obviously well suited to effect their purpose. Salter, in his original desc^ription of Protospongia from the Cambrian of Wales, compares it with Acanthospongia of Griffiths from the Silurian of Ireland, the original specimen of which he had seen ; l)ut says it has six-radiat(> spicules. He also remarks that the spicules of Protospongia seem to be all in one plani'.' P. Major of Hicks is a still older species, from the Lower Cambrian or Longmynd series, and seemingly of different stru(!ture and of much more open texture than that above described. Matthew has also noticed and figured fragments of Protospongia from the Lower Cambrian of St. John, New Brunsw^iiik. The present species, though somewhat later in age than the foregoing, has the merit of presenting a better state of preservation and better illustrating the general form, and more especially the root-spicules. The following remarks are quoted verbatim from Dr. Hinde : — " There are some differences of opinion as to the character of the spicular mesh-work and the systematic position of Protospongia, and fresh light on the ijoints contested is afforded by these Quebec siK'cimens. It has been doubted whether the body-wall of the sponge merely consisted of a single layer of spicules, or whether this layer corresponded to the dermal layer in other sponges of 'this group, and, as in these, was supplemented by an inner spicular skeleton, The evidence of the Quebec specimens favors the view that the body- wall of the sponge consisted only of a single layer of spicules. Various opinions have likewise been held as t<> whether the body-spicules were free, and merely held in their natural positions by the soft animal tissues, or whether they were cemi'nted together by silica at the points where their rays are in contact. Prof. Sollas, in an able jiaper on the structure and afHnities of the genus (Quart. .Tourn. Greol. Soc, Vol. XXX, p. 3fl(3), asserts that they are separate, and not united either by envelopment in a common coating or, by ankylosis ; ' whereas it would seem that a certain degree of organic union must have existed to have allowi'd even the partial preservation of the mesh-work of the body-wall in the fossil state, and I have regarded the delicate film of pyrites, which extends over the mesh-work in many specimens, as indicating a connected spicular membrane which served to hold the larger sj)icules in position. From the study of the Quebec sp ^cimens I still think a certain degre*' of organic attachnient existed where the spicular rays wer*' in contact, but I am quite prepared to admit that it was not of the same comi^lete char- acter as in typical Dictyonino hexactinellids. Prof. F. E. Schulze has clearly shown that a certain degree of irregular coalescence takes place in the body-spicules of undoubted Lyssakine sponges, and now that we know that Protospongut was furnished, like most of the sponges of this group, with anchoring spicules, there is good reason to regard this and the allied Palucozoic genera as belonging rather io the Lissakiue than to Dictyonine hexactinellids. This is the position assigned to them by Carter and Sollas." ' Journal Geol. Soc, vol. xx. 40 DAWSON AND HINDE 2.— Protospongia mononema, S.N. (Figs. 5, 6 and 1. PI. Ill, fig. 8.) Genentl size about one inch in diameter, originally globular but now flattened. Body spicules cruciform and more slender than those of P. ietranema. Superficial or defensive spicules very numerous and somewhat long and slender, so as to give a hirsute am bul cul anc nu: wt doi Fig. 5.—ProtoKpongia mononema. Rt-stored. Fic. 6. — Protospongia mononema. Cruciform and pro- tective spicules, X ,"i, appearance and in flattened specimens often to obscure the body spicules. Root, single, stout, often three inches long, with two to four short spreading braiichi's at base. These terminal spicules are flattened at the extremilies. Ilinde remarks that some si)ecimens seem to have two or more anchoring rods ; but in all or most of the specimens showing the pof spi coi: AJ \ Fio. 7. — I^otospongiu mononema. I'riinary, seiondnry and tflrtiaiy 8pimileH. X 5. this appearaucA' these seem to have been loose rods drifted into contact with the sponge. The anchoring rod in this specii's is often iiKjreased in tliickness by a crust or frosting of pyrite, and this would seem to indicatethnt it had, like the modern liyiilonema, animal matter as well as silica in its composition. a Is spi th( ON FOSSIL SPONGES FEOM METIS. 41 ttened. cial or dirsute This species is nearly as abuudant as the preceding, and is often seen without the anchoring rods while the latter are also often seen detached. In comi^arison with the previous species the root spicules arc not only quite different, but the skeleton of the body differs in some importai j^)articulars. The cruciform spi- cules have somewhat longer arms and form wider meshes, while they are very slender and scarcely at all thickened at the nodes. The surface is also invested with very numerous superficial or protective needles, giving a hispid appearance at the edges, while the meshes of the central part are obscured by the superficial spicules flattened down on them. The form and character of the osculum or oscula have not been observed. ■o- single, These jimeus owing 3. — 1'rotospongia coronata, S.N. (Figs. 8, 9, and 10. PI. Ill, fig. 4.) Fig. 8. — Protospongia coro- nata. Restored. Fia. 9. — Proiospongia coronata. Primary, secondary and protective spicules, x 5. Body ovate, small, 2 cm. long, spicules coarse and four-rayed, so connected as to give the appearance by their obliqiiity of a diagonal network of rhombic openings. This may possibly be the effect of flattening. Numerous small cruciform flesh spicules. Root spicules strong, short or broken off, 2 to 4. Osculum large, terminal, covered with a conical hood made up of curved spicules converging to a point, and 1 cm. in height. A few short superficial spicules visible at the sides. Fio. 10. — I'rotofipoiigia coronata. Showing internal cavily. pollge. ting of iinimal This is a small but interesiing species, remarkable not only for its conical hood, but also for the rhombic meshes and the development of the nodes of tlie larger cruciform spitniles, as well as for the stoutness of the latter, their rays bei7ig much thickened toward the centres. Sec IV, 1S80. G. 42 DAWSON AND HINDB 4, — Protospongia polynema, S.N. (Figs. 11 and 12. PI. Ill, fig. 5.) This is a large sponge in great shapeless flattened patches, several inches in diameter though there are smaller individuals also. Body spicules fine and slender, making a very Fig. 11. — Protospongia polynema. Portion of base of large specimen. open mesh. At base numerous simple root spicules, short, and, in some cases, expanded at their extremities. Young individuals seem to have been globular and probably sessile, while large individuals had a flat base, but the general form is greatly obscured by crush- ing, especially in the larger specimens. lo: if be or dt pt in th cr Fia. 12.— rroto/<}yongia pohjmma. Primary, secondary and tertiary spicules, x 5. It may be a question whether two species may not be included under the above specific name. The larger specimcuK have much more open meshes while the smaller are more hispid. These differences may, however, depend on age. I hav<> attempted only a partial restoration of this species in fig. 11, as the speciuu'us do not show with certainity the form of the upper part, which I imagine however, had long protective spicules. ci ON FOSSIL SPONGES FEOM METIS. 43 5. — Peotospongia cyathiformis, S.N. (Figs. 13 and 14. Pl.JII, fig. 5.) Fio. 13. — ProtoKpongia cyathi- formis. Restored. Fig. 14.—Prolospongia cyalhiform.i». Primary, secondary and tertiary cruciform spicules, x 5. Greneral form inverted conical. When mature about 3 cm. wide at top and 5 cm. long without the anchoring spicules which are at least an inch long. Top truncate as if with a wide osculum, with a few short defensive spicules on its margin. Primary- body spicules cruciform with long rays, in some 2 to 3 mm. in length, loosely attached or free, but forming large rhombic meshes, secondary and tertiary spicules numerous and delicate with slender arms. Root spicules short, simple, about five visible in the most perfect specimens and passing up to the middle of the body. Indications of many interior minute flesh spicules often constituting a pyritised mass, obscuring the meshes. The oblique character of the transverse spicules deserves notice, but this may be the result of compression, though I think it more likely that it is an original feature. This species is well characterised by its form, and by its multitudes of very minute cruciform spicules. These and the fact of the sponge being often represented by a dense pyritous mass iudiiate a thick and fleshy body-wall. 0. — PliOTOSPONaiA DELIOATUTiA, S.N. (Fig 15.) l<"i(i. 15. — Proioiipongui (hliculula- (») Restored. ('*) I'ortidi) of liasc eularsred. Globular or oblong in form, from 1 to 4 cm. in greatest diameter. "Body spicules cruciform, very numerous, and extremely small. Some specimens show what seems to 44 DAWSON AND HINDE bo a wide osculum above, and very numerous slender anchoring spicules below. There are also indications that, in mature specimens, the general form sometimes became cylin- drical or inverted conical, though specimens showing these forms are too imperfectly preserved to show the details of structure. In this species and P. ci/athiformis, the wall of the body seems to have been denser than in the other species and sometimes to have preserved its outward form, and this, with the multitude of minute spicules and the undeveloped condition of the spicular meshes of the skeleton, may possibly indie -te a generic differouce. On this species Dr. Hinde remarks : — " This sponge has a subcircular outline ; the central area is A'-acant and there is often a relati\ ely wide rim of a blurred mass of iron pyrites with an outer margin of fairly large cruciform spicules. The iron pyrites evi- dently represents a mass of spicules too small and too closely associated together to be separately distinguished in their replaced condition. The sponge is clearly hexactinellid and quite distinct from the others described above." Genus CYATIIOSPONG^IA {C/jathophi/cm), Walcott. 1. — CYATHOSrONOIA QUEBECKNSIS, S.N. (Figs. IG and lY. PI. Ill, fig. 1.) Tin. 10. — Cijalho.ijwngiti QuelitrmifiK KcstoriHl. Fig, I'.—Cijdthoi^ongia Qiichicenin!^. Base enlarged. Form elonirated conical, composed nppnrcnlly of numerous lonir, vertical spicules, crossed by horizontal or aiinnliir bars, and with a few cruciform spicules in the meshes. The vertii'ul and transverse spicules may l)e crviciforni spicules arranged veriically. The form terminates downward in a blunt point with indications of a few short anchoring spicules. This species closely resembles Cyathophycus {Cijnihos/iongia) reliruUUm of Walcott r,v>.«sl ON FOSSIL SPONGES FROM METIS. 43 from the Utica shale, but dilFors in detail, espotially in simplicity of the vertical rods and development of the transverse or circular bars. The largest specimens are 8 cm. long- by 8 wide at top. There are signs of minute lateral defensive spicules. The general form and structure resemble those of the modern sponges of the genus Holascvs. The species Cyathophijcvs relirulahis was founded by "VValcott on specimens from the Utica shale, but, as it has not been thoroughly described, the following notes, for much of the material of which I am indebted to Dr. Ilinde, may be useful : — In the collection of minerals of the late Mr. .T. S. Miller of Ottawa, purchased for McGrill UniA'ersity, are a few fossils, some of tht^m Canadian, others from the phosphate deposits of South Carolina. Among the former are a few specimens of Utica slate fossils, which, from their appenraiu-e I suppose to have been collected in the beds of that forma- tion near Ottawa, though it is possible that some of them may have been obtained from the United States. They iucludt.' a specimen of the above species, which Mr. Ami, who has collected extensively in these beds at Ottawa, informs me has not yet occurred to him. The specimen is a small slab of the ordinary Utica shale, having an impression of a glabella of Triarthrus on the back, which proves its geological horizon. It has two specimens of Cyathophycus close together, nearly perfect at their bases and broken off at the height of about three inches. They are perfectly Ihittened and pyritised, which is also the condition of other fossils in these shales, with th(^ exception of the graptolites, which seem io have resisted this kind of change. The genus Ci/athophijcm was originally described by Walcott from specimens obtained at Trenton, Oneida Co., New York.' He regarded it as an alga, whence the termination •phyctis; but subsequently, in the ' American Journal of Science,' 1881, corrected this error, and ref»>rred it to the sponges. Hall (•S.'jth Regents' Report) properly places it with the reticulate sponges included in his family DictyOHpongidcc, but does not add much to Walcott's original description, to which the present specimens permit some additions to be made. The specimens are perfectly flattened, but show distinct indications of the two sides of the originally conical form. The wall of tlie skeleton has evidently been thin and composed of slender bundles, each of a few long simple spicules, and increasing both by bifurcation and the introduction of new bundles, .so as to preservt^ nearly the same dis- tances in the wider parts of the cone. They are very reguhir in th(> lower part, where there are about nine principal, with some intermediate secondary bundles in a centimetre, ])ul they become more irregular toward the top. This may, however, be an effect of decay and crushing. At the l)as<' tliese bundles become thicker, and in a specimen from th(> original New York locality, kindly lent to me l)y Mr. Ami, I have ol)served that they become expanded and converted into sonu'what short clavate root spicules. This is, however, not apparent in Mr. Miller's specimens, which may liave been broken olFat the surface of the mud. The vertical bundles ar(> crossed at right angles by horizontal spic^ules much less regularly arranged, Init dividing the surface into rei^anii'ular meshes. The.se are .slightly l)li'jue and rhomboidal in the specimens, but this is probably due to pressure. The iqiK ' Trans. Allmny Instil., ISTii. 46 DAWSON AND IIINUE horizontal spicules seem to bo triarerate in form, and much shorter than those of the vertical system, though of very diflereut lengths. They are sometimes in bundles and sometimes solitary. In parts of the substance, apparently -within the reticulate wall, may be seen a few cruciform spicules, and Ilocculent patches apparently of An^ry small spicules, which seem to have been mostly internal and most abundant toward the base, but cannot be distinctly made out. The wall is very delicate, and consists of quadrate or oblong areas formed by slender longitudinal and transverse strands or fibres, of which the former are the more prom- inent. As in Protospougia, the quadrate areas are formed by the four transverse rays of cruciform, or fiA'e-rayed spicules, but these are disposed so that their rays overlap each other, and thus form fascicles of closely opposed parallel rays. The spicules in the trans- verse strands of the wall are less thickly grouped together, and even in some of the larger squares they may be arranged singly, whilst the smaller squares are generally bounded by single spicules only. The longitudinal strands principally consist of cruciform (?) spicules, but it is possible that elongated filiform spicules may likewise be present. There are plain indications of a fifth or distal ray in many of the principal spicules of the wall, shown by a very minute knob or blunted process projec'dng from the central node of the transverse rays, which may represent a partially developed ray, or the broken stuinp of a complete one. In some places, also, there is a continuous film of pyrites, probably indicating a membrane of very minute spicules or an agglomeration of flesh-spicules., now replaced by this mineral. The basal portion of these specimens is incomplete, but then^ are indications of an extension of the longitudinal strands of th(* wall downward into a spreading tuft of short anchoring spicules widening at their di.stal end.s. This genus is mainly distijiguished from Protospongia by the fascicular arrangement of the spicular rays iu the principal longitudinal and transverse fibres. The regular quadrate areas of the body-wall also mark it o(F from Plecloderma and Phoriiiosella, Hinde. (See Brit. Foss. Sponges, Pait. I, PI. Ill, figs. 1, 2 and Part. II, p. 124-5, 1'al. So.., 1880-37.) How far it may resembh^ Dldi/ophylon,^ Hall, and the other genera associated therewith by Prof Hall (SSth Report of the State Museum, 1884, p. 1G5, pis. 18-21), it is impossibh^ to state, for the structural features of this genus have not been sullieiently described, and the characters assigned to the other genera are mainly those of (>xternal form, which, as ri'gards tiiis group of sponges, are hardly of gejieric- importance. The structures of Cyathophycus, ..s , hown in these speciaicns, bear a great resem- blance to those of th(^ recent genus Ho/asc/.'i, Schulze (Challenger Reports, Vol. XXI, p. 85), based on sponges dredged from depths V'"ying between 1,375 and 2,050 fathoms in the South Atlantic and in the Southern Ocean.- There is a striking simihuity in the .struc- ' In the only species of the DictyosponjiidiT! in wliich I luivo seen structure, that named by Whitfield Uplimi' knia Dawsoni. Am. .loiirii. of Science, Aiij:., ]8Sl, and I'lUlletin Am. Num. Xut. Hist , Uci'., 1881, the siiieide.s are appparently lililonu and arraniied in hnjud l()ii;.'itudiiud and transverse bundkss •nissiu'; each otiier, and with small, loose flesh-sjiicules in the mcslies. Tlie arran^rement is tlierefore dillerent lU details from that of ('ijaOio- 1iliijcw>, or, as it should luiw he called, VijathoKinnxjia. The name 'lij(1roctrn» proposed by Conrad, is liable to the objection that it was intended to indicate allinily lo cephalopo I shells.— .1. W. 1). -' Kaijecially 11. fihtUulm, Schul/.e. dial. liep. N\i, liir. \K ON FOSSIL SPONGES FEOM METIS. 47 tu^e of the sponge-wall iu the fossil and in the original specimens described by Schulze, no"^ in the British Museum of Natural History. The whole of the spicules, in the Utica as in the Quebec group specimens, are com- pletely pyritised, and appear under the microscope to be made up of rows of cubical crystals of pyrites. They were probably originally siliceous, but this need not excite surprise, as the silica of such spicuh'S is in a condition which facilitates solution, and in some modern sponges the si>icules are not purely siliceous, but contain some animal matter. I have also notice.I other cases in which siliceous Palaeozoic sponges have experienced this change, while in many specimens the spicules have entirely disappeared. This is the case with the Erian or Devonian sponges of the genus Diclyopkyton and allied genera, which, owing to their apparently membranous character, I at one time believed to be fucoids, but abandoned this idea on seeing the specimen of Uphantmnia (Phi/sospongia, Hall), which Prof. Whitfield was kind enough to show me in the New York Museum in July, 1881. In a note communicated to Prof. Whitfield in August, 1881, I have made the following remarks on the pyritisation of sponges : — " The most puzzling fact iu connection with the original siliceous character of these sponges is their mineral condition, as being now wholly replaced by pyrite. Carbonaceous structures are often replaced in this way, and so are also calcareous shells, especially when they contain much corneous matter, but such changes are not usual with siliceous organisms. If the spicules were originally siliceous, either they must have had large internal cavities which have been filled with pyrite, or the original material must have been wholly dissolved out and its place occupied with pyrite. It is to be observed, how- ever, that in fossil sponges the siliceous matter has not infrequently been dissolved out, and its space left vacant or filled with other matters. I have specimens of Astylospongia from the Niagara formation which ha\e thus been replaced by matter of a ferruginous color ; and in a bundle of fibres, probably of a sponge allied to Hyalomena from the Upper Llandeilo of Scotland (since named Hyalostelia by Hinde'), I find the substance of the sjiicules entirely gone and the spaces formerly occupied by them empty. It should be added that joints of Crinoid stt'ms and fronds of Fenestella occurring in the same specimen with the ITphantppnia are apparently in their natural calcareous state." The type of structure of Cyathophycus is essentially that of th(^ Hexactinellid sponges of the suborder Dictyo7iina of Zittel, and under this, as has already been suggested by Barrois, it belongs to the family of Dictyospongidcc, established by Hall for Dictyophyton and the allied sponges of the Eriau rocks. This type, already known as far back as the Utica shale, is now carried a stage farther by our discoveries at Metis. The spongi's of the genu.-, Ci/alho/ihycvs are not abundant in the beds explored at Metis and most of them have been much broken up. Only one specimen was obtained as a tolerable state of completeness. Genus AOANTHODICTYA, Hinffc. Sponges approximately subcylindrical in form, consisting of a skeletal mesh-work of longitudinal and transverse spicular strands or fibres. The longitudinal strands are ' I have similarly explained Piiritouium oi' 'Sh'Coy niul Eophijlon c.rphimtttim of llKka.aBh&aH'mde a\ao, in Geol. Mag., 1886. 48 DAWSON ANI> IIINBR composed of somewhat loosely arriuigcd I'aseicies of elongated overlapping spicules, and the spicules of thi' slender transverse fibres arc as a rxile disposed in a single series. From the outer surface of the sponge, numeroiis spicular rays project outwards at right angles. The sponge appears to have been anchored by a basal prolongation of the longitu'iinal strands. Owing to the present compressed condHion of the specimens it is difficult to determine the original form of the constituent spicules. Some of the elongated longitu- dinal si^icxxles may be merely simple rod-like forms, others are clearly cruciform and their transverse rays form the cross-fibres. The spicular rays which form the projecting bristles of the surface may be the free distal rays of normal hexactinellid spicules, but only thesi! projecting rays can now be clearly distinguished; the others are merged in the longitudinal fascicles. The general structure of the skeleton resembles that of Cyathospongia, Walcott, but it is characterised by the presence of the projecting surface rays. The mesh is also of a looser character than in Cyathospongia and its arrangement in quadrate areas is only faintly recognisable. 8,— ACANTHODICTYA HISPIDA, Hinde. (Figs. 18 and 19. PL III, fig. 8.) Fig. 10. — AcantJiodiclya M/fida. — Portions enlarged x 5, showing framework and cruciform and protective spicules. Fig. is.— Acanthodictya hispida. Restored. The examples of this species are apparently nearly cylindrical tubes from -SO to 50 mm. in length, and about 12 mm. in width. The longitudinal fascicles are about 1 mm. apart and the tra.isverse fibres from 1 to 2 mm. distant from each ovher. The projecting spicu- lar rays of the surface are only seen in these compressed spong-es at the lateral margins as a sort of fringe. The free rays are somewhat thickly set ; they vary from 5 mm. to 8 mm. in length ; the lonn-er 1'orms in some instances ot.'cur at regular intervals, probably at the angles of the mesh, and between these are the shorter rays. The extremilies of many of the larger forms are slightly swollen or club-shaped, but it is uncertain whether this is ON FOSSIL SPONOES PROM MKTIS. 49 an original feature or is due to an irregular deposition of the pyrites which has now in all cases rei)laced the silica. This species appears as ribba"'1-like hundi: composed of vertical and parallel bundles of delicate spicules with slender transverse spicules crossing them at intervals like the rounds of a ladder. It was probably originally cylindrical, but the extremities have not been ::;e<^n. though fragments nearly three inches in length have been found. One; of its most conspicuous characters is the possession of dense fringes of long protective spicules at the sides, and these seem to be based on a cortical structure of crutch-shaped or cruci- form spici'.les from which the defensive spicules spring. Scattered cruciform spicules of small ai'M appear also in the middle of tin' bauds. The fascicles of longitudinal spicules are sometimes loosely twisted in a s^iiral manner, and it is probable that the root-fibres were spiral. Il^ponges of the above species are sometimes associated with the larger masses of Protospongia in such a manner as to suggest a jiarasHic or commensal relation, but this may be accidental, and Uiay arise from the cortical spicules of Acanthodictya be(,'oming entangled with the surface of neighbouring sponges. It is possible that some of the spirally twisted anchoring rods mentioned below may have belonged to this species, but its root spicules have not been seen attached. The genus no doubt approaches to Cyathospongin, but is separated by its cylindrical form, the fascicled character of its longitudinal rods, and its cortical spicular arrangements. Genus IIYALOSTELIA, Hmde. 9. — Hyalostelia Metissica, S.N. (Fig. 20.) Fig. 20. — Hyalostelia Metissica. Spicules x 5, and large spiral anchoring rod magnified. This species has not yet been seen in a perfect state or showing its general form. It seems to have been of a specially friable or decomposable character. The body appears as irregular patches of broken up skeleton, which, under the lens show a confused mass of cruciform spicules large and small, slender rods and some peculiar triradiate spicules, apparently in some cases with obliqut^- angles, though this may perhaps be a result Sec. IV, 1889. 7. 80 DAWSON AND EINDE of distortion, cruciform spicules with one ray curved, and minuto stellate spicules. The whole somewhat resembles, though with difference in detail, the debris of the body of the modern Hyalonema, when crumbled and examined under the microscope. Associated with these patches, and also found separate, are many large anchorincf rods of peculiar structure. They consist of several slender spicules twisted togol "ily so as to resemble a rope. Each strand has little tuborolcK externally to give greater holding power, and the whole, when well preserved, constitutes one f^f the most beau- tiful of sponge structures. In one or two cases the spiral threads were seen to be unwound at their proximal pnds, as if passing into the slender rods of the body of the cponge. A tendency to such spiral rolling appears in the modern glass-rope sponge {Hyalonema Sieboldii), and the little frills on its root spicules may represent the tubercles 01 the strands in the present species. A similar structure has been found by Dr. Hinde i.a the root spicules of Hyalostelia fasciculus, McCoy, from the Siluro-Cambrian,' and a specimen apparently of the same species in my collection shows this structure, though less perfectly than the specimens from Metis. The connection of these anchoring rods with the patches of scattered spicules is of course inferential, but they are constantly associated on the slabs of shale, and such roots are not found attached to any of the other species, though, as already stated, similar roots may have been present in Acanthodictya. Imbedded in some of the patches of Hyalostelia are oval bodies, about a centimetre in their longest diameter, destitute of roots or defensives and composed of crowded cruciform spicules of minute size resembling those of P. delicatula. I was at iirst disposed to regard these as gigantic ovarian capsules, but Dr. Hinde thinks they are more probably small sponges of some other species accidentally introduced. Genus LASIOTHRIX, Hinde. Sponges small, depressed oval in outline, the outer surface covered by a layer ot longitudinally arranged, apparently simple, acer.vte spicales ; beneath this is another layer of spicules disposed transversely. From the bate of the sponge several simple elongated spicules extend. The peculiar arrangement of the surface spicules in this form indicates a probably new genus, but in its present condition one cannot tell with certainty whether it is monactinellid or hexactint^llid. The outer suriuce seems to have been invested with a sheathing of regularly arranged acerate spicules, and beneath these other spicules, disposed transversely, can be distinguished, but whether these are really acerate or modified hexacf^^inellid spicules there is no decisive evidence to how. In one or two instances, the spicule^; appear to be cruciform, and the presence of the long simple anchoring spicules extending frona the base of the sponge, precisely as in normal hexactiuellids, is a further point in favor of its belonging to this division. ' British Fossil Sponges, PaL Soc, 1888, PI. i. fig 3. ON FOSSIL SPON(}ES FItOM METIS. 81 10. — Lasiothbix curvicostata, Ilinde. (Fig. 21.) Tho type form is traiisversoly oval, 8 mm. in height by 12 mm. in width, tho anchoring spicules can be traced to a length of 15 mm. from the body. The summit is rounded. There are some nodular elevations of pyrites in the body portion, but it is Fig. 21.— Lasiothrix curvicofitata. Natural. 8i/e and portion eulargoJ doubtful whether they represent aggregations of spicules or are merely due to the chemi- cal deposition of the mineral, in connection with the presence of organic matter. This curious little sponge, of which only one specimen was foiind, is remarkable for the strong curved spicules which support its sides, giving the appearance of a rounded basket with strong vertical ribs and very slender horizontal bars, within which and at top were quantities of slender straight spicules. 11. — Lasiothrix flabellata, S.N. (Fig. 22.) Fio. 22— Lcmolhrix flahdlala. Rostorod, and spicules x 5. I have some doubt as to the right of this species to be placed in Dr. Hiude's new genus ; but the specimens at first sight resemble the former species, and may accompany it provisionally. The surface appears to be covered with small ovoid bundles of stout biacerate spicules, diverging from the oeut"e and sometimes in fan-shaped tufts. The specimens show indications of an external membrane, 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 llattened groups of radiating spicules surrounding small oscula. In some specimens the spicules are confusedly scattered in films of pyrit- 52 DAWSON AND IIINDK oUH maltcr with litth' indication oi" nuliiiting arrangfuiciit. Dr. Ilindc remarks aH to this i'orni that "the npicult'S do not stand out dt'finitfly, as in the case of tho hoxactintdlid hpongo spicuh's, but ai)p([ MMTIS. 83 rods, which may iiidicatft the character of tho body of (lie Npongf. (Fig. 24.) These spieuh^s were proljably defensive rather thaji for anchoring. (3) Groups of extremely delicate simple straight spieules lying close together and paralhd or more or less disturbed. They are narrow, and may have hi'vn eylindrieiil. One group has four long anthoring rods arranged in two pairs. They show no indica- tion of cruciform spicules. (I'ig. 2.').) Fici. 24. — Spinose .sponge. Natural hIzc. Fifi. 25. — Group of .S])i(;ules enlarfjod- (4) Groups of fine sh'nder spicules either parallel or divergent. Frobably root spicules of some species of hexactinollid sponge, and not unlikely Aainthodidya hispida though there is no certainty as to this. (5) Large and long solitary spicules, simple and straight, sometimes 0.5 mm. in thickness and several inches in length. They seem (^uite smooth, but are sometimes flattened at one end. (6) Flattened masses of irregularly coalest^ent fibres like those of lithistid or corneous sponges. They show no anchoring spicules and are irregular in form, and have their structures very imperfectly preserved. Nos. 2, 3, 5 and 6 are of rare occurrence in comparison with the other forms. Ollur Ornanhmfi in the Sdine Beih, ()15(1LET,I,.\ (LiNNAKSSONIa) PItETIOSA. Bill. (Fig. 26.) I'ld. 20.— /,?'»)((( rsoii/(( ;)r(7/o,«(;, Billings, n, nuUir.al size of inediuin si>0(!iniens, h, ventral, c, dorsal valves. In my preliminary note this was compared witli O. Ida of Billings, but according to Prof Hall, who has kindly examined it, it belongs to the Cambrian genus Lin- 34 DAWSON AND HINDE narssonia of Wiilcott, and is not distinguishable from Obolella pretio?r and Cape Rouge, near Quebec. It is allied to O. sagittuHs, Saltt^r, from the Welsh Menevian, and which also occurs in the zone of Para- floxicks Forcliammeri in Sweden. This genus is thus, so far as known, characteristic of beds older than th(> Levis ; but there is no reason why it might not occur thus far up in the series Shells of this species, usually pyritised, but sometimes black and flattened in the plane of the shale, abound in the layers holding sponges. I figure (Fig. 27), from drawings supplied by Prof. Hall, the structures of this little shell as they appear in some of the best specimens.' Cystideanl — A small jointed stem, 1 cm. in length, with an elongated flattened mass at one end, in which, however, no distinct plates can be seen. Traih of Annelids, etc. — On some surfaces are flattened and rounded grooves of difier- ent sizes, but mostly small, and which may be trails of aquatic animals of different kinds. They are not pyritous and present no trace of organic matter. Some of the larger are spiral in the manner of Arenicolites spiralis, and these are pyritous. BUTHOTREPHIS PERGRACILIS, Dowson. (Fig. 27.) Fig. 27. — BuOiolreplm jicrgracilh. Stems \cry lono; and flcxuous, aboiit 1 mm. in diameter, and obscurely striate longi- tudinally ; sending olf at their extremities short alternate or opposite branches. Allied to B. gracilis, Iltill, of the Siluro-C'ambrian, but much more elongated and slender. These plants are rt>placed ])y pyrite and usuiilly llaiteiied, but the branches are occasionally cylindrical, which s»>ems to have been the original form. On some of the suri'aces are groups ofmiuute round pyritous spots, prol)al)ly of organic orin'in, and jxThaps ova or ovi-capsules of spctimes or other animals, perhaps ihe vegeta- tion or iruetiiicalidu f some a(iuiilie plants. Tlieri^ are also a lew oval or round, jx'rfectly flat or smooth, discs resembling flattened vesicles. On some of the slabs are i .Seo apiKinded Note. ON foslsil sponges feom metis. 85 also groups of more minute rounded bodies with no distinct structure, except in a few cases an apparent uotcli at the margin. They may be spore-cases or ova, but perhaps are not organic. An interesting point in connection with these remains is the appearance of so many distinct types of siliceous sponges in one locality and formation, and this of so great age. It is also deserving of note that these sponges are of types usually occurring in deep water, and- if we regard the dark shales containing them as deep-water deposits, this might account for the absence of other fossils. The alternation of these shales with coarse conglomerates and sandstones would also imply great oscillations of level at the time of their deposition. The occurrence of so many species of sponges in very thin layers of shale, for the most part unfossiliferous, in connection with the obscure and unobtrusive character of these remains, is also an indication of the imjiortance of thorough study of the older formations, and of investigation of even their more unpromising portions, as well as of the exhaustive exploration of those jiortions in which fossils occur. i NOTE. Description of Linnarssoma cnf. pretiosa, Billings. By Prof. James Hall, LL.D. Shell small, subcircular or elongate transversely. Valves subequally convex, the ventral beak erect, slightly projecting and perforated at its apex. J'^xternal surface covered with fine concentric lines, faint radiating striaj being visible on the interstitial lamellre. The interior of the ventral valve bears a sublrianguiar or U-shaped ridge, the branches of which divei'ge anteriorly. The thickest portion of this ridge at the union of the branches is penetrated by the foraminal tube. In front of the fora^vien, and Just within the cardinal lino, on either side tlio axis of the shell is a conspicuous tuljcrclo or boss. In the dorsal valve is a median I'idgo, extending half tiic length of tlio 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. (The above description bus been kindly supplied by Trof. Hall from si)ecimens sent to him from the Peter Redpath Museum. — .T. W. D.)