Section IV., 1886. [ 3B ] Tuanh. Roy. Soo. Canada, IV. — On the Silurian System of Northern Maine, Neio Brunamck and Quebec By L. W. Baii i:y. (Read May 11, 1880.) Since tho time of the publication, i>. 1842, of Dr. A. Grosner's Fourth "Report on the Geology of New Brunswick," the Upror Silurian age of the extmisive tract comprising the northern counties of this Province lias been generally iccepted; the fossils collected from various localities along the St. John River, and again in the counties of Restigouche and Gloucester, indicating an ho'-izon about that of the Niagara or Lower Helderberg forma- tions. In his " Geology ol Canada " for 18t)8, Sir W. fi. Logan described at length tho same formation, chiefly r-^ foiiud in the Province of Quebec, under the name of the " Gaspe Limestone" series, at/iie same time referring to its northern base as being found on Lake Temiscouata, where, a high ridge abutting upon the lake, known as Mount Wissick or Mount Lennox, ar 1 abounding in fossils, was regarded as resting unconformably upon a series of b'^ds at ;jne time supposed to be Devonian, biit then referred to the base of the Quebec gioup.j' In Northern Maine also the same formation had been early recognized by Jackson, r.nd was subsequently more fully investigated (in 1800) by Packard and Hitchcock, the latter describing the Silurian rocks as found at Lake Sedgewick (Square Lake) and some other points, and which were richly fossiliferous, as being unconformably overlaid by a series of red shales and conglomerates, referred to the Devonian. In the meantime the limits of the formation in New Brunswick remained for the most part undefined, and were variously located by different observers. It was not until 18V9 that, by simultaneous observations on either side of the St. John River, in Carleton county, made by Mr. G. F. Matthew and the author, something like satisfactory data upon these points were obtained ; the unconformity of the Silurian system with the associated rocks, more particularly along the Beccaguimic valley, being then established upon the triple evidence of the composition of the conglomerates at the base of the former, the discordance of dip between the two, accompanied by progressive overlap, and finally of fossils, the lower rocks being found to hold a fauna apparently indicative of the age of the Trenton. In the same valley, at its mouth, a series of coarse conglomerates had been previously found by Mr. Chas. Robb to contain thin seams of shale abounding in remains of Psilophyta, and, upon the evidence of these, the beds containing them, together with a somewhat extensive tract of other coarse sediments occurring about the headwaters of the Ber and of somewhat dilfcrent aspect, appear to be older, and may be Silurian. A little higher up siliceous slates again appear, but these now contain calcareous bands, from which, in 187!i. Mr. Matthew succeeded in obtaining a number of small shells, chielly of a species of Lepta-na (allied to L. (/er.i/nens of Billings), as well as others apparently of the genera Liii'^iilellti, Sirojiltoineim and Discina, to which later collections, made by myself, Mr. W. Mclnnes and Mr. W. T. Reed, have added several, though fragmentary, specimens of the trilobite genus Ilnrpes. There can be but little question that these beds are of Cambro-Siluriau age, either Tienton or lower, and they tend to confirm the view so long entertained that this is the real age of a part at least of the great bands of slates and quartzites which constitute so marked a featiire in the geology of this part of New Brunswick. Passing now to the hills which, at a distance of a few rods only to the north, over- look the valley at this point, we meet with strata of a widely dill'ereut character. Among these is a band of grey conglomerates and grits, in which are contained numerous frag- ments of black siliceous slat(! and quartzite, apparor.tly identical with that of the beds in the valley below, cemented by a calcareous paste, in which, as observed by Mr. Matthew, are contained numerous encrinal fragments. These conglomerates, which at a short dis- tance to the north are followed by heavy beds of limestone, are regarded as the base of the Silurian system, and, with the associated limestones, containing numerous fossils, have been traced for considerable distances through the adjacent country. A ridge of these conglomerates crosses the North Branch valley three miles aboA'c Shaw's Mills (their high inclination being again strongly contrasted with that of the red Lower Carboniferous con- glomerates near by), but between these points are other beds which give further interest to the exposures of this vicinity. These consist of a series of sandstones and slates, of which the former are often grey, purple or chocolate-brown in colour and in aspect not at all unlike some portions of the Lower Carboniferous formation, while the slates are dark-grey and black. Both are fossiliferous, biit in the sandstones the fossils are few, consisting of scattered relics of Crinoids, Orthocerata, and Brachiopods, mostly frag- mentary, while the shales on the other hand, at least in certain layers, abound in the remains of Graptolites. These were at first believed by Mr. Matthew to contain diprionidial forms, but, in larger collections subsequently made, none of the latter could be detected, while a further study of the adjacent district confirmed the idea that both the slates and sandstones were of the same age as the gray conglomerates, and all Silurian. It only remains to state, with further reference to this region, that here and there SYSTEM OF NOIITHMKN MATNR. 87 through thoso Silurian sandstonos may bo Ibund the; remains of branching plants, while at ono point, in dose proximity to the siliceous beds first described, is a small exposure of quartzose rock containing an abundance oJ' what are evidently Psilophyta, apparently undistiiiguishable from those lound by Mr. liobb near the mouth of the river. As tho conglomerates in which the latter occur are not unlike those describ'.^d above as forming part of the Silurian succession, and as the plant-bearing beds above Shaw's Mills are almost certainly of this age, it is at least possible that all these rocks are really Silurian rather than Devonian, as some of them have been supposed to bo. I now pass to the region of the Fish Kiver lakes in Northern Maine. The description of the rocks found in this vicinity, as given in Hitchcock's " Report on the Geology of Maine" (IWlil, pp. 42(»-42-l) is from the pen of Prof. A. S. Packard, jun., who, however, does not hiniself exjircss any oi)inioii as to their age. Among these rocks the most interesting is a band of highly fossiliferous limestone, outcropping on the western shore of Sqiiare or Sedgewick Lake, and wiiich has to some extent been locally employed as a source of lime, h'rom collections made at the locality by Packard and Hitchcock, the late Mr. Pillings succeeded in recognizing about forty distinct species, of which fourteen were new, while my own visit to the locality, though short, enabled me to obtain a some- what greater number, inchiding, as determined by Mr. Ami, two additional species not hitherto described. These fossils have been regarded, both by Mr. Billings and Mr. Ami, as being of Lower Helderberg age, and the enclosing beds, in this as in other respects, may be regarded as the counterpart of the limestone beds of the Beccaguimic region, in New Bruns- wick. Associated with these beds on Square and Eagh; Lakes, and apparently enclosing them, there are, as described by Packard, ledges of red shale and conglomerate, with l)eds of grit, the conglomerates containing fragments of dark slate and jasper, and dipping 45' to the northward, in which direction they are followed, first, by bull'-weathoring fossiliferous sandstones and then by dark clay-.slates, which, with other slates and sandstones, occupy the remainder of the country northward and eastward to the St. John liiver valley. A like succession was observed on the thoroughfare from Portage Lake, a few miles west of Eagle Lake, and at Ashland. All the rocks of the above section have been regarded by Prof. Hitchcock as Devonian, and are so represented in his map of Northern Maine, as they are in that accompanying the last edition of Sir "Wm. Dawson's "Acadian Geology." If how- ever the above relations are as supposed, it would seem altog-ether probabh; that the great bulk of strata here met with is, as on the Beccaguimic, of Silurian rather than Devonian age. I may add, from personal examination, that in almost every particular the beds of the Fish River lakes bear the closest resemblance to the beds which accompany and enclose the limestones of the Beccaguimic valley. It is true that no grajitolite-bearing beds were here observed, but beds of A'ery similar character occur, while even on the Beccaguimic these beds are but thin. Moreover, in both instances the sandstones exhibit the same peculiar Lower Carboniferous aspect. Both contain similar remains of crinoids and shells, mingled with stems of plants, while the conglomerates in both are also alike in containing numerous fragments of black slate associated with others of bright green and red jasper. If to this we add the fact that, beneath the conglomerates, etc., above described, we have, on the shores of Portage or Nadeau Lake, connected with the other or westerly branch of Fish River, a well defined 38 L. W. BAILEY ON THH SILUIJIAN belt of (lark f^rcon silicooiiH rIiiU*,' doHoribcd by riukiird luidcr thw name of hornstono, and (•()nlaillillJ^• luasisiv*' beds ol' brij^ht red clKirty Nlatc, with a nearly vtn-tical dip, \vt' appear again to liave a rcpt'titiou ol" the rehvtiouH iimnd on th(^ IJeccaguiniic, these cherty Nhites bi'ing, as wo believe, tlie equivalentH ol" the (linty slatoH ol' Shaw's Mills and, like tht* latter, of C^unbro-Silnrian age. Tht! following tabular view will seive to makt* this parallelism more evident : — 1.— nKXKAflUIMIC SkotION. A, Cnmlirii'SiiHridii. Uliick TOlciirco-silicodUS slatos, witli IjrarhiojxxJs and trllobites. 15. Sihirian. 1. (iii'v ('iilfiiriMiUB coiinloiiiortiti's ami i!ritn, liol(liii)r fni(;inoiitM of liliick .siliceous slnti's iiiifl inmrtzite, ,inH|K)r, viU'-, miii^'lod witli nmiiiiiis of criiioiil.s. 'J. Ciroy, rodilisli 1111(1 iiruwii saiidHtiiiutH and NJutcH, unhoi'IuUmI with IilhIh of roNHilifei'oDH liiiiuHUtiie. li. (iroy ('im;:loniorat«s. 4. tlroy, cidciiruiius iiikI bufl'-woiUliorinK Bandstonea, with wtom.s ciC crinciidH and slu^lls. 5. Gr^ty and dark k^')' slates, with ^'raptolitcH anil reiiiriiuK of iiiantx. (). Urey, bluiNli-weathorinf,' and calcaicMius alati'H. * 2.— Fish RiVBft Section. A, Camliro-Siluriun f Dark clicrty slatois, with hands of jas|)or. 1!. HWnriini. 1. Cirey ''alcareous conglnmoratcs ? not ohaorvod. 2. Grey, reddish and hrown sandstones and shales, assoiuated with beds and t'ontaininf,' enclosed miieses of fossiliferons linie8ton(\ 3. Grey, calcareons coniilomerate, with [xibliles of dark llinty slato, jasper, (»t('. 4. Grey, calcareous and buff-weatlierint.' sandstones, with crint)icls and shells. 5. Grey and dark grey slates, with remains of plants. 0. Grey, bluish-weathering, calcareous slates. I pass now, thirdly, to the Temiscouata region. Between the latter and the region of the Beceaguimie in Carleton county, the St. John River affords an admirable section of the Silurian system, without, however, exposing- any beds which can with certainty be regarded as representing its base. For nearly the whole distance of one hundred and fifty miles, including the Madawaska River and the southern half of Lake Temiscouata, the only rocks seen are slates with occasional alternating beds of fine sandstone, mostly of grey or dark grey colours, but occasionally red or green, the beds of this latter coloiar being usually associated with beds of impure hematite. They are very generally calcareous, and at times highly so. but no actual beds of limestone occur. They are also at muiiy points fossilift^rous, the fossils including species similar to those of the Beccaguimic, and, like the latter, appearing to indicate an Upper Helderberg horizon. Finally^ they have been subject to extensive disturbance, the plications being general and of the most complicated character. The first beds of a markedly difTerent aspect from the above are met with upon the ' These beds bear some resemblance to tb(( beds of Pointe aux Trembles or Temiscouata Lake, to be presently described, and their true position, in both instances, is somewhat uncertain. HYHTRM OF NOimiKRN MAINK. 39 Tuhulic liivi'V, not far from Hh mouth, and iijynin on tho shore of Lake Tomisroxinin, at a point nearly opposite the Tuladie, where they are alluded to in the eliihorate Hectioii of this vitinity, given by Sir W. E. Logan, as '• tlie beds of Pointo aux Trembles." These roeks are massive sandstones, of somewhat dioritie aspect and witli bands of purphi jasper, which pass into and include beds of cong'lomerate, the piibbles and matrix of which aw. both composed of dark grey or puridish-grey porphyritic petrosilex, mingled at times with fragments of black slate. Above these beds on the shores of the lake, but stratigraphic- ally beneath them, the rocks next seen are shales and slates, alternating with sandstones, in which we have lately obtained fragments of ribbed shells. Sirailar beds are well exposed at the Tuladie Falls, and like Die Silurian slates on the shores of th(' lake, have a pretty uniform south-easterly dip of lif. The iu>xt beds north ant those of lllack and liurnt Points (vii/e Logan's section), and are again composed of conglomerates and sand- stones, but with the former now greatly predominating and having (juite a different aspect from those of Pointe aux Trembles, being not only very coarse, but of different com- position, the pebbles consisting largely of metamorphic rocks, such as quartzite, white sandstone, mica schist, etc., mingled with many of limestone. These beds have also a south-eastward dip of 50-tJO°, and a measured thickness of nearly 1000 feet. They are further described by Logan as probably belonging to the Quebec group, and as being unconformably covered by the limestones of Mount Wissick next to be noticed. An interval of about 1500 yards separates Burnt Point from the eminence last named, on whose almost precipitous north-western face (attaining an elevation of 550 feet) a most renujrkable and interesting section of the rocks composing it may be seen. The order of succession and the thickness of the beds, as condensed from Logan's Report, is as follows : — Fkkt. AVliitisli iiias.si vo saiulstone 4,5 Grey course calcnreoiis coiitiloinerato, with jjebbles of limestone and (iiiartz. 20 Measures concoaleil , vieM'ing the above, it would appear that, in the view of Logan, the line of separa- tion between the Silurian system (Gaspe limestones) and that of the Quebec group is to be found at or near Pointe aux Trembles, all the strata north of the latter, except those of 40 L. W. BAILEY ON THE HILURIAN Mount Wissick, atul iuchuliiij? the heavy cong'loincratoN of Hlack aii>l Kurnt I'oiiils mid tho rockH of tho Tuladif and ('al)auo, hi'iiip; it'lcrahlo to that ^^Toiip, whiK^ thoso to the noulh, toj^cthor with thoK»» of Mount Wissick, an; to bo rcfi'ircd to tho Craspt Limostono sorios or Silurian. It is, howovor, to bo obsorvod that Sir William himsolf sooms to havo boon in doubt upon this point, for whilo on ono page (42!{) h(^ doscribos tho (•on^•lonu'ra(<'s of IJlack Point as Ix-longing to tho (iuobco group, ho subs('(|U('nlly rofors to thoiii (i)a<,''o 427) as being novvor lliaii tho latter. On the other hand, the very siriking reseniblanees which portions of those beds ))ear to Ihose of tho UeccaguiuMc and Ihe Fish Itiver lakes cnn hardly fail to attract attention. Thus the conglomoratos of IJlack Point, though vastly thicker and coarser than anything soon in Now IJrunswick or Maine, apparently occupy (he sarno position as thoHo describi-d on the soulherii side of the great Silurian plateau. They are, iiuleed, compared by Logan with a certain band of conglomerates met with near (ho mouth of the Siegas, lifty or more miles to tho south, in the Silurian tract, a comparison which further indicates tho uncertainty of opinion in which they were held by him. Again, both the green and rod shales and fossiliferous limestones of Mount AV^issiek, though as regards the latter of much greater thickness, occupy tho same relative position and bear much resemblance, both in aspect and in their fos.sils, to those of Fish River und thi' Beccaguimie. These fossils include largo corals {lumosites) Biachiopods {Slro/jhomfiiti, Lepta-na, Pentumerns, etc.), besides several species of Trilobites, and are probably of Lower Holderberg ago, but until they havo been accurately determined this comparison is uncer- tain. Tho most remarkable diU'erence in tho Mount Wissick beds, as compared either with those of the Becraguiraic IJiver or the Fish ]{iver lakes, is that all'orded by tho massive white sandstones or quartzites Avhi< h form the apparent base of the eminenco referred to. No such rocks are to bo met with anywhere over tho extensive Silurian tracts of Northern Maine or Now Brunswick. They do, however, bear much resemblance to the beds of like composition seen at frequent intervals along the Portage road between Temiscouata and Riviere du Loup, and again along the line of the Intercolonial Railway between the Metapedia Itivor and Rimouski. Tho greater part of these, however, l)elong to the Quebec group, while those of Mount Wissick are interstratilied with the fossili- ferous limestones of the mountain, and are unquestionably part of thi' same formation. I am also informed by Mr. R. W. Ells that similar sandstones were found by Mr. Richardson to contain remains of Pentumerns ohlotigus. As the beds underlying them at Mount Wissick are almost entirely of the Quebec group, these quartzites would appear to form hero the lowest member of the Silurian system, which would also appear to include all the bods of Lake Temiscouata south of this point — among them the conglomerates of Black and Burnt Points and the rocks of Pointe aux Trembles previously referred to tho Cambro- Silurian. The Temiscouata section, as compared with those of northern Maine and Nt'W Bruns- wick, previously quoted, would thus stand as given on the succeeding page. I may add that, since reading the above paper, further examinations of the region about Lake Temiscouata, as well as of j)ortions of Aroostook county, Maine, have been made, and numerous fossils obtained from Pointe aux Trembles, Tuladio Lake and else- where. These are now in the hands of Mr. Whiteaves, and the results of their examination will appear in the reports of the Geological Survey. SVHTKM Ol-' Noiri'llKim MAINK, 41 AndKNIiINU RKnTftiN iiK Sll.l IIIAN l{(l('KS, LaKK TnMIW!<)rAlA. A. l'iiiiiliri)-Silui'inii. (l^iiulxu! (It'(iu|i,) (iruoniitli, ruildiHli luul bhu'k HliituM, IntiuliMl witli Uiiu liiyerH uf ilolntnitic liinoatunu. B. Siliiriiui. Pkkt, WliiTisli hiiikImIoiioh 200 CiilciirodiiH coiiKliiiiutriitus mill HiiiidNtoncs, with linmHtiiiio jKtbMns 130 Iti'd iiiid grc'oii slmlt's, iiicliiiliiit; I'd.ssiliriTiiUM liiiii'ulipiui.s l'J5 Groy nodular linio»toiM«, iibdunding witli I'oswilN, and iiiclmliiiK' hands (if liurd HundHtonu 580 Meusurcs ctinccalcd 127(1 ('(iii;;liiniLn'at('H {i>{ Wlark and Itmiit Points), witli iHihlildS of Candiro-Sihn-ian rw.ka, including hniostoiuiM 1000 Moaaurcs concoalud. Dark shali^H and Handntonps, with foHsils. Oroon and imrpliHli Handntoiii's and con'^donicrati^i, fmniin); I'ointo aiix Tri'inhlos. Groy-bltiish weathering slates and sandstones, continuous with those of Maine and New IJrunswick. Sec. IV., 1880. (i.