IMAGE EVALUATION TEST TARGET (MT-3) // «*^ m IFrom the Qttarteelt Journal of the Geological Society for August 1894, Vol. 1.] Note on the Genus Naiadiies, as occurring in the Coal Forma- tion of Nova Scotia. By Sir J. William Dawson, C.M.G., I,L.D., F.R.S., F.G.S. With an Appendix by Wheelton Hind, M.D., B.S., F.R.C.S,, F.G.S. [Plate XX.] In the autumn of 1892 Dr. Wheelton Hind was so kind as to invite me to place in his hands, for study and comparison, specimens of the bivalve shells from the Coal Formation of Nov9 Scotia, which I had described under the above generic name, ^ and some of which were described by the late Mr. Salter in the Quarterly Journal of this Society, vol. xix. (1863), under his new generic names Anthracoptera and J.nthracomga. Owing to illness I was unable, at thb time, to comply with Dr. Hind's request, and thur^ the Nova Scotian species lost the benefit of a detailed comparison with the British forms in Dr. Hind's excellent paper of May 1893.'' I have now sent a col- lection of specimens to him, and beg to make the following remarks thereon. These she?'- occur plentifully in some of the argillaceous shales of the Coal j. ormation, and occasionally on the surfaces of flaggy sandstones, but the most abundant repositories are the beds which I have named ' calcareo-bituminous shales' and ' bituminous lime- stones,' beds which, on account of their superior toughness and black colour, often stand out prominently in the coast-sections, and are sometimes almost entirely composed of these shells.* As none of the properly marine species of the Carboniferous Limestone ever occur in theto beds, and as they are closely associated with the coal- seams, I have always been greatly interested in them — in connexion with the various theories of the deposition of coal. I referred to them in this relation in ' Acadian Geology,' 2nd ed. 1868,'* in the following terms : — " All the lamellibranchiate shells, which are so numerous in some of the shales and bituminous limestones of the Joggins that some of the beris nay be regarded as composed of them, belong to one generic or family group. They are the so-called Modiolas, Unios, or Anodons of authors. I proposed for them, some y^^ars ago, the generic name of Naiadites,^ and described six specie^ ^rom the Coal Measures of Nova Scotia, stating my belief that they are allied to Unionida), and that their nearest analogue may be the genus Bysso-amdonta of D'0:bigny, found in the river Parana. ' ' Acadian Geology,' Suppl. 1st ed., 18G0. '^ Quart. Journ. Geol. Soc. vol. xlix. p. 245). ^ See sectic of the South Joggins, iu ' Acadian Geology,' 2nd and later editions. * Pp. 202, 2U.i. ^ ' Aeudiini Gi-ology,' Suppl 1st txl. , 43G 81K J. W. UAWSON ON NAIADITES IN [Aug. 1894, Mr. Saltei', however, to whom I sent specimens, regards these shells as belonging to his new genera Anthracomya and Anthracoptera, the former being supposed to bo allied to Myad. 438 DR. IVHEELTON HIND ON NAIADITRS IK [A.Ug. 1 894, Measures, a fact wliich was recognized by the late Mr. Salter, who, in a description of Sir William Dawson's shells, Quart. Journ. (Jeol. Soc. vol. xix. (1863), substituted the names of his nowly-erocted genera Anthnicoptera and Anthracomya for Naiaditcs, notwith- standing the critical objections raised by the author of the name Naiadites. I have been in correspondence with Sir William on the subject, and propose to retain the name Naiadites for the form called Aiithracoptera. In my paper published in this Journal, vol.xlix. (1803), p. 249, 1 figured and showed that Salter's Anthracoptera had a striated hinge- plate, a character, the absence of which had been considered to separate the genus MyaVma (Be Koninck), and in Ueol. Mag. 1893, p. 514, I published a note on Myalina crassa, pointing out that there were no anatomical features by which the shells known by that name could be .separated from Salter's AntJiracojdera, at the same time noting that the septa within the beaks described by De Koninck were absent. On looking up De Koninok's original description and figures I find in 1842 (' Descript. des Animaux Fossiles,' p. 125) the following description : — " A Tintericur et immodiatementau-dessousdo ceux-ci [the umbonos], une jjetite lame septiforrae, scmblable a celle (]ue Ton observe dans certaines cspeces de Mytilus." The figure given is too imperfect to shoAv these characters. In his more recent work, ' Faune du Calcaire Carboni- Icre,' ^ he describes the genus and says it is " muni d'une cloison intt'rieure," but the figures, especially figs. 5, 7 and 1), pi. xxix., demonstrate most conclusively that this septum did not exist in them. Prof. King (' Permian Fossils,' pi. xiv. figs. 5, 7 »&; 12) shows shells from the Permian which appear to possess this myophorial septum, to which he gave the names Mytilus sqnamosiis and M. sejjfifcr, but in the text he suggests their reference to De Koninck's genus. M'Coy (' Brit. Palaeozoic Foss.' p. ■^.92) says, in his description of Myalina, that there is " a triangular septum in the cavity of each beak, parallel with the plane of the lateral margins, leaving deep slits under the beaks of the cast," but he mentions no specimens from the Carboniferous series. When in the Brussels Museum a few months ago I was unable to see any signs of the septa in De Koninck's specimens, and think it probable that many of his forms will have to be placed with Naiadites, the name Myalina being retained for the septiferous forms from the Permian, and for any which may appear in the Lower Carboniferous series, [It has been thought advisable, at the suggestion of the Council and with the assent of the author, to incorporate here the f Dllowing synonymy of N^aiadites. — En.] Ann. ITist. Nat. Musro roy. do liolpiquo, vol. xi. 1885. Vol. 50.] VnE COAL-FORMATION OF NOVA SCOTIA. 439 1840. 184;'.. 184;-.. IH;->(J. 1853. 1854. 1855. 18(50. 1801. 1802. Sywonymy OF Naiadites, Naidea, Swainson, for r'?uo-like molluscs. Ncr'^-n, Buckinan, ' Geology of C'heltenliam,' Rhactic and SlonesfiolJ plants. Naiadita, Brodie, Fossil Plants (in ' Fossil Insects'). Naiadita, Buckmaii, adopted in Quart. Journ. Qeol. Soc. vol, yi. p. 415. Uawson figured several Molluscs from Nova Scotia resembling Modiola and Unio, Quart. Journ. Geol. Soc. vol. x. (1854) p. 39 Naiadites, Morris, for Naidea and Naiadita, in his ' Catalogue of British Fossils.' Dawson again figured one of these molluscs a3 a Modiola, 'Acadian Geology,' l.st ed. p. 148. Dawson gave a short description of the shells and referred to the above figure, provisionally naming it Naiadites. He described also several species ; the first and tyjie species being Naiadites earbonarius. Sup- plement to Lst ed. ' Acadian Geology,' p. 43. Salter gave the name of Anthracomya to certain British Coal-measure molluscs with full descriptions and figures, Mem. Geol. Surv., ' Iron Ores of Great Britain,' pt. iii. p. 229. Salter speaks of three species of Naiadites he had received from Dr. Dawson, namely Naiadites dongatus, N. carbunariiis, and N. leevis. The first and last of these he refers to Anthracomya, and for the other, iv. earbonarius, Dawson's type, he proposes the name " A/ithracoptera for these triangular shells." If the name of ' Naiadites ' can be retained for any of these molluscs it must be for this type-species N. earbonarius, for which Salter erroneously proposed the generic name of Aiithracoptera,Q,uart. Jouru. Geol. Soc. vol. xix. (1803) p. 80. Note. — Wheelton Hind, 1893 (see below), says that the form figured by Salter, Qi"irt. Journ. Geol. Soc. vol. xix. p. 79, fig. 3, as Anthrucoptera carbona.'ia is not the same as Dawson's type, ' Acadian Geology,' 1st edit. p. 148, and Quart. Journ. Geol. Soc. vol. x. p. 39. & 1878. Dawson gives figures and descriptions of these Nova Scotian sheila and partially adopts Salter's names as sub-genera for some of the species, thus: Naiadites (Anthracopfcra) carbo?iaria, Naiadites (Anthra- comya) clovgata, Naiadites (Authraeoptcra) Itevis ; but speaks against Salter's idea of the marine nature of these shells (as quoted above, p. 430), 'Acadian Geology,' 2nd & 3rd edit. p. 202 et seqq. Wheelton ITind adopts Salter's two genera Anthracomya and Anthru- coptera, ,jr the British species, but says that the specimen from Nova Scotia figured by Salter as Anthracoptera carbonaria is not the same as Dawson's Naiadites earbonarius ; the latter, Hind says, is an Anthracomya, Quart. Journ. Geol. Soc. vol. xlix. (1893) p. 249. Wheelton Hind in tiie MS. of the present paper proposed to adopt Naiadites for Anthracomya, and to retain the name of Anthracoptera for the type-species of Naiadites. He now acknowledges that Salter's Anthracoptera carbonaria is the same as Dawson's Naiadites earbo- narius. The genus Naiadites, therefore, will have to be usctl and Anthracoptera discarded. The British forms referred to the latter geuus, in the author's 1893 paper, will now be called Naiadites. I must admit the error of which I am convicted by Sir William Dawson — namely, that I confounded Naiadites leevis and Estheria Dawsoni — the more so as the fault was due to carelessness in com- paring the numbers of quoted pages. I am not able to state that any of the species submitted to me are the same as British forms, therefore the specific names must still remain, though, if at any time in the future more perfect pppcimcns an^ nbtaitinblo. it may bo quite possible to do so. 18(i8 1893 1894 440 DR. WnEEr.TON niNI) ON NAIADITE8 IN [Aug. 1 894, I have a aorios of spccimeiiH from the South Joggins hibolled by Sir J. Williiitn Dawson Anthracoptera carhonarw. They existed ill very largo iiutnbers in some of the shales of the South Joggins, 80 much so that the greater part of the mass is composed of debris of this shell, with entomostiaea and vegetable remains. I have little or nothing to add to Sir William's original specific description, but would point out that his original ligure is very misleading, and that jS'aiadites carho^nnnn, Dawson, differs much from the figure of Anthracojtiera carlxmaria, Salter (Quart. Journ. Gool. Soc. vol. xix. 18(53, p. 79), and it was this difference which led me to suppose that Dawson's original specimen was probably Anthracomya (Quart. Journ. Geol. Soc. vol. xlix. 1803, p. 249). The umbones were not shown to be terminal, and were described as " acute in the anterior fourth of the shell," while I thought Salter's figure was that of a specimen of one of his Anthracoptera'. I am bound to say that Salter's figure more nearly represents the shells which have been sent to me as Kaiadites cnrhonarius. In shape this form approaches somewhat to that of Naiadites {Anthra- coptera) modiolaris, but the umbones are more raised above the hinge-line, more pointed and not curved anteriorly at the apex. There is one s})ccimcn which reveals a typical interior with finely striated hinge-plate, bevelled at the exterior of its outer edge, with trifid anterior mnsculir scars, and relatively larger posterior- adductor scar. The posterior end was often sinuated above. The periostracum shows the typical characteristics of the genus. There exists, as with us, an elongated form, probably only a variety of this shell ; but it evidently comes from a different bed, the matrix being a hard, fine-grained, micaceous sandstone (PI. XX. fig. I). It would seem to have been less gregarious in its habit, if one may judge from the paucity of its remains in the specimens to hand. It is very difficult to be absolutely sure as to the generic position of the shells figured as Anthroconii/a elongaia, as there arc no specimens showing the hinge-line, ligament, or muscle-scars, but from the shape they probably belong to this group. There is nothing to add to the original description, but I think that the sen- tence describing the position of the umbones is misleading. It says, " the beaks obtuse an*' more anterior," but it is difficult to see what is the meaning of the word more.^ It cannot refer to the shell previously described, which is a Naiadites {Anthracoptera) carbo- narius, and has its umbones very forward ; while, comparatively to the length of the hinge-lino, the umbones in iV. elon,^atus are sub- central in the specimen figured. There appear to have been two forms or varieties of this shell, one more elongate and comparatively narrower, the other short and as broad as long. With regard to Anthracomya arenacea, the specimen which Sir J. W. Dawson has sent me is typical of Salter's genus ; it is allied to the forms found on the Continent, and known as Anodonta f A plpi-ical m-or for ' less.'— J. W. D.. Mht 1804. Vol. 50.] THE COAL-FORMATION OF NOVA SCOXrA. 441 Ooldfimiana. Tho original drawing in ' Acadian Geology ' does not 8ho\v tlio gradually oxpamling jiosterior end, and would give tho idea that the original was an Anlhmcosia. I think the specimen from tho McUiU College Collection labelled Naiadites elongatus belongs to this species. This specimen is nearly 1 inch long, and shows tho typical shape and contour. Naiadites angulatus (Dawson) I considor to be \ inthmcosia a pretty little form of typical shape. In the original drawing tho posterior-superior angle is too much prolonged backward. Anthracomi/a ovalis is a somewhat larger, more tumid shell thiiu Naiadites eloiu/atus, to which it approaches. I think that the shells in a block of Millstone Grit from Riversdale belong to this form ; if so, it is interesting to note the presence of the same form in tho Upper Coal Measures of the Joggins. Anthracomj/a la-vis is very similar to a shell which is obtained, only crushed flat, from the Wigan coal-fteld ; tho English specimens are, however, larger. Prof. Amalizky has fallen into error as to the value of the term Naiadites, and in his work on the Anthracosida) of the Kussian Permian, 1892, has erected Naiuditts into a genus of tho new family Anthracosida3, resemng the term for a set of shells totally different from the majority of those for which the name was invented. I have shown above that originally the genus included Naiadites carhonariiis. „ clongattis. Anthracomya arenaeea. „ ovalis. Anthracomya Uevis. f Carhonicola 1 , . [Anthracosia\'"'y''''-'*''' I shall take an early opportunity of combating other views on this subject contained in Prof. Amalizky's work. EXPLANATION OF PLATE XX. Coal-Moaaure shells from the South Joggins. The figures are of the natural size, when not otherwise stated. Fig. 1. Naiadites, B\-i. Elongate form. (Unfortunately tho artist has inverted tho figure.) 2. Naiadites carbonarius (Dawson). 3. „ „ showing interior. Muselo-pits. 4. Anthracomya arenacea (Dawson). 5. „ ,, probably young. fi. „ „ probably young. T. Anthracomya cloncfaf a (Davrson). x2. O. ,, M II X—. 9y 2 • M II II /N *^' 10. „ „ „ X2. ' It is highly probable that the term Anfhracosia, King, must give way to Carbonico/a, M'Coy, on the grovmd of primnty, although the hit tor's description of the hinge-plale is erroneous. 442 NAIAD1TE8 FROM NOVA 8C0TU. [Aug. 1894. Fig. 11, 12. 13. 14. Slub with (a) Aiithrncomya elongata, (h) Anthracomi/a, sp. ? (e) Naiaditca carhonarina, (Collection of tbo Gcol. Survey of Oaimda.) Anthracomt/a hevin (Dawson). Anthracomya ovafin (Dawson). Horizon of tlio Millstone Orit. 1 Anthvdcosia (King5 | «"•'/«'«'« (Dawson). [Note.— Sj)(Timen.s 1, 4, .") belong to Sir J. W. Dawson's coUeotion in llie Mc'Gill College, Moiiireal ; .8l»ec-iineiiH 11 & 13 t() tiio Oeologioal Survey of Ounatbi. Tbe rcnminder liavo been presented to uio bv Sir J, W. Dawson.— W. H.l Quoirt. Joum. Geol. Soc . Vol, L , PI . XX. a 'i0fi^->*iV ', ,1 ''n A.HSearle del.et:iit.- Mir^tern Bros. intp. :'.,>vLrMf:ASUFii-: shf:ll,s krOxM: tiik south joguINo.