Section IV., 1884. I 91 ] Tuans. Koy. Soc. Canada. 
 
 IV. — Oit Geoloyical GonlavtH and Ancient Eroaloii in tSouthern and Central New 
 Jirumivick. — liij L. W. Bailev. 
 
 (lUind May '2\i, 1884.) 
 
 The importance ol' goologii-al contacts in the determination oi' the structure and 
 geological history of ditfereut regions is well iiuderstood, and in the study of the latter 
 these receive, as they deserve, especial attention. While the various formations, in their 
 petrological characters, their thicknesses, and their contained fossils, all'ord the data for 
 estimating the conditions of their origin and (heir relative duration, it is along their lines 
 of junction that we are to look, more than elsewhere, for information as to the circum- 
 stances under which they came to a close ; in other words, for the time and nature of tho 
 physical breaks by which the historical record is dividrsd into its separate chapters, and 
 made comparable with those of otlier regions. 
 
 In the study of the geological structi;re of the Province of New Brunswick, which, as 
 regards its general features, is now well advanced, a variety of such contacts has been 
 observed and detailed in the geologic^al reports. From the peculiar position, however, 
 which this Province occupies with reference to the great north-eastern or Acadian basin, 
 and from the i'act of its possessing a larger number of determinable horizons than any 
 other portion of that basin, of which it thert^fore becomes to a (Hirtain (ixtent the key, the 
 consideration of these contacts has an interest beyond the immediate region in which they 
 are found, and suggests conclusions of much wider application. It is the intention of tho 
 writer, in the following remarks, to consider briefly some of the more important of these 
 junctions, and the deductions which they may seem to justify. As the passage from one 
 formation to another is usually accompanied by evidences of more or less extensive 
 erosion, and as this, in some instances, affords almost the only proof of a w^ant of continuity, 
 6ome observations on this latter point may also prove of interest. 
 
 The reference of a portion of the rocks of southern New Brunswick to a pre-Silurian, 
 Azoic, or, as it is now better termed, Archean age, was first asserted by the writer in con- 
 nection with Mr. Gr. F. Matthew in 1865, on the groxmd of their relations to the fossil- 
 iferous rocks of St. .John, then first identified by Hartt as containing a typically Primor- 
 dial fauna. It is remarkable that, while the recognition of this ancient horizon is 
 not exceeded, as regards the completeness of the data, by that of any subs ec|uent formation, 
 so its relations to the underlying rocks are of the most satisfactory and <;onclusive charac- 
 ter. For not only do they differ wholly in lithologicai characters, a feature which some 
 writers suppose to have been the only gi-ound for their separation, but, in every particular 
 ordinarily marking discordance of successive fovmations, the evidences here ofl'ered are 
 wide-si>read and complete. Whatever view be taken as to the precise equivalence of the 
 underlying groups which have been compared respectively with the Laureutian and 
 Huronian systems, the fact remains that these rejn-eyent a A'ast thickness of sedimentary 
 
92 L. W. IJAILKY ON fiP.OLOOICAL CONTACTS AND AN(!IENT 
 
 sfrata of the most divcrso diaraotcir, and that, whilo at ono point the Primordial rt'sis upon 
 what appear to l>i> the most ri'ccMit ol' these strata, at another it reposes upon beds which 
 cannot be less than several thons:nids ol' feet lower in the series, while the conglomerates 
 which mark its base bear further testimony, both in Iheir composition and their thick- 
 ness, to the erosive processes which preceded or accompanied the deposition of the Pri- 
 mordial sediments. Finally, while local unconformable contacts may be seen at many 
 points, an eqiaally marked discordance is observable in the two uroups as a whole, the 
 trends of the Primordial beinu' transverse to those of the supposed Huroiiian, as the folds 
 and disloi-ations of the ont! arc (|uite indei)endent of those of the other. The Lower Silu- 
 rian, or Cambrian, formation is thus as clearly defined in its stratigraphical relations as it 
 is in its paleontological features, and forms a readily recognizable horizon, with reference 
 to which the ]iosition of both older and more recent groujis may be directly compared. 
 
 As regards the older systems to which rel'erence has b»M'n made, New Brunswick has 
 been naturally looked to as likely to afford somi^ information upon the questions which 
 have recently awakened so mu(^h attention, regarding the number and order of succession 
 of the pre-Cambrian rocks, and has, indeed, been frequently referred to in discussions of 
 this subject. It can, however, I think, hardly be said that these questions, as here applied, 
 have yet received a definite solution. That there are among the rocks referred to three, 
 if not four, distinct groups of strata, exhibiting strong lithological contrasts, and i)ro- 
 bably representing entirely distinct periods and conditions of deposition, was early recog- 
 nized and has been confirmed by all later study of the ri'gion, but the precise relations in 
 which these stand to each other and their correlations with proposed siibdivisions of 
 Archcan rocks elsewhere, are not so easily settled and have been variously regarded by 
 different observers. Thus, while the writer, in common with Mr. G. F. Matthew, by whom 
 the structure of the district was first studied, has described, in what he believes to ha an 
 ascending succession, a gueissic, a calcareous, afelspathic, and a schistose group, — the two 
 former being regarded as representing the Laurentian and one at least of the latter the 
 Huronian system, — Dr. Hiant has been disposed to question the existence of true Laixren- 
 tian in this district, and to modify the above arrangement by associating the calcareous 
 with the schistose group, regarding both as newer than Huronian and equivalents of what 
 he has elsewhere termed Montalban. Without attempting to deny that such an arrange- 
 ment is possible, and that, if sustained by further investigation, it would bring the succes- 
 sion in this region into remarkable parallelism with that observed elsewhere, the 
 writer, after long and repeated study of the region, is still constrained to think that th(5 
 facts of the case are such as to favour the former rather than the latter view of the actual 
 structure. Thus, applying the test of contacts, which it is the purpose of the present paper 
 more particularly to consider, it is not a little remarkable that while the calcareo-silicious 
 group may be seen at many points resting upon, and in direct contact with, the coarser 
 gneisses, following these throughout their distribution, and apparently involved in the 
 movements by which they have been affected ; nothing at all resembling the strata first 
 named is to be found in connection with the schistose group, where the few limestones 
 which are met with are very impure, of insignificant thickness, of different character, and 
 of wholly unlike associations. Again, if the calcareous and associated strata are really 
 more recent than the felsite-petrosilex group, the entire absence of the latter between the 
 same calcareous beds and the underlying gneisses, when these are observed together, 
 
EROSION IN SOUTllKRN AND ('KNTRAL NKW BlfUNSWKJK. 93 
 
 wouM imply an iimoxiut of oroHiou which, (•oii.sidori'it'' tho naluro of tho matorial coiuhok- 
 iiig llio I'olHitii! f^Toiip au<l the vaHt bulk which it exhihitH ovon at a vory limitod distance, 
 seems altof^ether impr()l)al)le. It may ho added ihiit while pel)hlef,, derived alike I'roni the 
 felsiiic and schistose beds, occur abundant ly and in j^Teat variety in the hasal conu;lomerates 
 of tho I'riniordial, no such pebbles from either member of the calcareous gro. p liave been 
 ideutified in such a position as they natxxrally would be in, were the latter group imme- 
 diately 8ubja<'ent. All that can at present be positively assorted is: (1) the sui)er-i)Osition 
 of the limestone-quartzite series ujjon the granitoid gneiss, though perhaps distiint from 
 the lattc^r, and (2) the interposition of a vast body of schistose strata, (|uite unlike those of 
 the lirst named group, between the felsitic rocks and the basal beds of the I'rimordial. It 
 may be added that between tho felsitic groirp and the overlying schists and conulomerates 
 the contacts art! abundant and easily observed, showing not only distinct unconfor- 
 mity of dip, but at least a ])artiai breaking up of the lower beds, accompanied by tlu! 
 extensive extravasation of igiu'oxis rocks and the formation of coarse tulls and atrglomer- 
 ates. Idled with blocks derived from the horizons beiu'ath. Adopting this vi(!\v of the 
 succession, it will be foimd to accord very nearly with that descril)ed by Dr. Kicks and 
 others as characterizing tho district of St. David's in Wales, where fossiliferous Cambrian 
 strata, containing a fauna similar to that of St. John, are in like numner underlaid in down- 
 ward succession by slaty and comparatively little altered rocks (Pebidian), a middle 
 group (Arvonian), comprising contem])oraneous volcanic rocks, felsites, l)reccias and i nil's, 
 and having a thickness of 15,000 feet, and a lower group (Dimetian) consisting' of urani- 
 toid and quartzo.se rocks v/ith coarse gneiss and bands of limestone and dolomite, The 
 Coastal, Coldbrook and I'ortland groups of the New Brunswick local reports present appa- 
 rently identical features both of origin and arrangement. We may now pass to iho con- 
 sideration of some more recent horizons. 
 
 In connection with the rrimordial or Cambrian rocks of St. John, no remains of 
 younger formations are to be met with, except it b(? those of the Lower Carboniferous 
 series, and although in the more northerly belt of such rocks, found in the .alley of tho 
 St. John River in King's County, these are approached somewhat nearly by fo.ssiliferous 
 beds of Upper Silurian age, no actual contact of the two has ])een observed. It is, how- 
 ever, to be remarked that while beneath tho Primordial rocks of this region there are, as in 
 St. John County, felsi)athic and schistose bods, succeeding in turn a well defined felsite- 
 petrosilex group, the latter is also directly and unconformably covered by the Upper Silu- 
 rian strata, thus indicating the extensive erosion to which the surface had been subjected 
 prior to the deposition of these later sediments, — a lircumstame made still more <onspicvious 
 by the occurrence of numerous hills, some of them several hundred feet in height, whi<h 
 rise like islands through tho nearly horizontal Upper Silurian beds, being evidently 
 fragments of a formation at one time much more widely distributed. The nature of these 
 beds and the fossils they contain show that the waters in which they were deposited were 
 but of moderate depth. 
 
 It has long been known that rocks of Upper Silurian age are widely spread over the 
 northern counti is of New Brunswick, and that these are bordered along their southern edge 
 by wide belts of much harder rock, flanking one or more belts of granite, and in the vicinity 
 of the latter often presenting the aspect of highly crystalline schists, this second group 
 being variously described by Gesner, Robb, Hitchcock, Hind and others as Silurian, Cam- 
 
94 L. W. HAILKY ON CfKOLOOICAL ('ONTA(TH AND ANCIKNT 
 
 l»ri!iii, Mi<u-K(lii.sl yroup iiiul Qut'l)t>c p^roup. Until within tho lasi year or l\v<», hovvcvt-r, 
 no (Iclinito l\novvlt'<lgu cxiHlfd, cillicr us to the tiuu limitH or relations ol'thoHi! several sets 
 ol" rocks, or oven whether in tho lower ffroup thero niiaht not really be iniliided several 
 distinct formations. In lH7!t, tho base of the Upper Silurian in that part of Chirleton County 
 lyiiifj- east of the St. Jolin liiver was approximately iixed by Mr. Mattlu^w, and, simulta- 
 neously ])ut independently, a like boundary was determined by myself between the town 
 of Woodstock and the Maine frontier. More recently both of these districts hav(! Ix-en 
 reexamined and the line of eontact of these formations carefully studied for a distance of 
 not less than thirty miles. Thonjfh sonu'what o])scured by overlying carlxmiferous s«>di- 
 nients, the unconformity of the two is, nevertheless, strongly nuirked : llrst, in the occur- 
 rence at the base of the ui)per series of thick beds of calcareous conglomerate lilled with 
 fragments (black silicious slate and petrosilex) derived from the group below; secondly, 
 in a dillerence both of strike and dip; and thirdly, ns a result of this dill'erence, in the pro- 
 gressive overlapping of the newer fornmtion upon the several members of the older. The 
 fossils of the later groiip art! numerous and varied, and indicate an horizon corresponding 
 cither to thai of the Niagara or Lower llclderberg; in the lower r.re a lew shells and 
 graptolites, together with fragments of trilo])ites, apparently of the genera Tritiui(rns and 
 ILirjics, l)ut too poorly preserved to be certainly determinable. 
 
 The relations of these sixpposed Cambro-Silurian rocks to the granite open up nume- 
 rous (juestions, as interesting as they are dillicuilt. They present, indeed, only another phase 
 of the well-known Taionic controversy, so admiraldy sixmmarized and discussed by our dis- 
 tinguished Vice-President in the lately issued volume of oxir Transactions. Into the broader 
 (juestions involved in this controversy it is not necessary, nor do I f(!el pre|)ared, to enter; 
 the objects of the present paper will be sulliciently served ])y presenting a few facts of 
 actixal ol)scrvation in the Held, with such conclusions as are of direct local application. In 
 the case of l)oth of the great granite })elts which traverse New Brunswick, the contacts of 
 the latter with the bordering stratified rocks are best seen along their northern edge, from 
 which overlying material has l)een for the most part removed, while it has been exten- 
 sively accumulated along that of the south. Where thus exposed it invariably presents 
 the following features : — 
 
 1. The transition from massive, compact and uniform granite to the associated schists 
 or other rocks is instantaneoias and abrupt. 
 
 2. The invaded ])eds vary greatly in (character, embracing coarse and fine gneisses, 
 mica schists, chloritic and hornblendic schists and fine micaceous sandstones. 
 
 3. Foliation and crystallization are most marked in the vicinity of the granite, and 
 decrease in receding from the latter, but vary greatly in the apparent distance to which 
 the effect has extended, this being in some instances only a few yards, while in others it is 
 several miles. 
 
 4. The outline of the granite is irregular, and, while in part parallel to the strike of 
 the enclosing schists, at others it intersects these obliquely or even at right angles, or 
 sends into the latter irregular tongues. 
 
 5. Detached masses or bosses, of various forms and sizes, bordtjr the main granitic 
 areas, indicating, beneath the schists, a wide-spread and ixneven granitic floor. 
 
 G. Granitic veins, not ditferent from the main mass of the granite, but readily distiu- 
 
KROSION IN SOUTJIKRN AND CKNTIlAli NKW BRUNSWICK. 98 
 
 guiHhublu from inn- sogivgatod veins which accompany them, ponotrate the s(;hiNls in all 
 directions to a dislancn^ of several hundred feet. 
 
 '7. Lar{?e detached blocks, of various sizes up to two or three f»M't, l)ut usually angu- 
 lar and sometimes ieclani:iilar, are enclosed in the granite, and product! the appearance of 
 a coarse granitic breccia. 
 
 To the al)Ove it may be added that sunill pat<heH, sometimes not more than a lew 
 yards or feet in extent, of gneissic or schistose rock, are oocasioiuilly met with resting 
 upon, but inseparable from, the granite, at very consideriible distances from the nearest 
 exposures of such schistose rock, while smalh^r masses, wliich are evidently detached frag- 
 ments, occur in all parts of the granite area, often retaining the same features of texture, 
 foliation, and even of colour, presented l)y the main body of such rocks. 
 
 From a consideration of the above and other Im^ts, the conclusion seems to 1)o fairly 
 established that the granites in (pu'stion are intrusive or exotic, and that the alteration of 
 the associated rocks was an accompaniment, if not an ellect, of such intrusion. It may be 
 added that while the several belts of slates and schists, north and south of, or central to, 
 the granite, have been variously described as wholly or partly of dilferent age or origin, 
 recent minute examinations of the region show beyond question their essential idt'ntity, — 
 the same crystalline and semi-crystalline rocks always appearing where the granite is 
 approached, whether from the southern, northern or eastern side, while in the o])posite 
 directions these as invariably graduate into the upper and comparatively unaltered argil- 
 lites and greywackes. At what period the extravasation of the granite occurred is less 
 certain. As far as yet observed in Carleton County, no veins of the latter are to be found 
 penetrating the Upper Silurian, although veins of syenite aiid diorite are common ; but 
 the fact ol)served in the southern co\inties, that the conglomerates older than the I^wer 
 Carboniferous are destitute of grauiti<' pebbles, while tho.se of the latter formation abound 
 with them, taken in connection with the evident similarity of the granites in the two 
 regions, and the precisely similar etfects accompanying them, appears to indicate that both 
 are of synchronous origin and both Devonian. In either case the amount of erosion which 
 has since occiTrred is sufficiently indicated by the facts already stated, the whole granitic 
 area, with a superficies of several hundred square miles, having been evidently laid bare 
 by the denudation of beds (schists, slates and sandstones,) which, though now miles apart, 
 were at one time continuous over it, and which, to jiidge from their highly inclined atti- 
 tude and vast thickness, must have buried it to a very considerable depth. The fact that 
 the granit(^ areas are usually lower than those of the bordering schists would also seem to 
 indicate that erosion has been more extensive and complete along these areas than in 
 the regions adjacent to the latter ; while the much greater breadth of the region of mcta- 
 morphisra and foliation on the northern side of the granite, than on the southern, would 
 appear to indicate a much more abrupt descent in the junction line of the granitic mass on 
 this latter side than iipon the opposite. It is to the contrasts thus produced that the different 
 views, which have been advanced by different observers as to the relations of the strata in 
 the district, are to be ascribed. 
 
 I pass now to the contacts of the Devonian. In the southern counties the rocks of 
 this age, so far as they have been certainly identified, are of very limited distribution, and 
 rest only upon rocks of Cambrian or pre-Cambrian age, a portion of these latter, by an 
 overturn and fault, being also brought to rest, in a position of comparative conformity, 
 
06 h. W. lUILKY ON OKOLor.K'Ari CONTACTS AND AN("IKNT 
 
 ii])<)U the l)('V'()iiiivii Hlnilii, iiiid Ihiis oriifiuiitinn' a miNfouccptioii wliidi Ibr Hoinn yearH 
 ol)srun'(l Mm IriK^ Nlrucluid of llio rt^jfion. No coulailH of Diivoniaii and Silurian aro to bo 
 round in (his pari ol" llm I'roviut'o; and thouj^h nwrh contact han ))i'cii HUppoHml to occur iu 
 connoction with the ari>illilt'H bordcrinj"' the central coal-liold, Iho ago and rclatiouH of 
 these rocks can hardly be rt>y;ardcd as delinitely nettled. 
 
 In risiiiii' to the jjower Carhoniierous, we reach an horizon and a sericH ol" conia<:tH 
 which, wlietlier they bo regarded isimply in themselves, or in their aecornpaninients of 
 erosion and lithological contrasts, constitute the most marked boundary lini! in the i)hy8i<'al 
 history of New Brunswick. Resting indiU'ennilly and unconlormably upon all the older 
 formations (Laurentian, Iluronian, ('uml)riaii, IVP'''' Silurian, Devonian and granite) ; com- 
 posed of material, in souu^ instances fossil iferous, derived from all thes(( formations, and 
 varying in its aspiut with the natur;' of the rock on which it rests; exhibiting no sign of 
 those metamorphic iniluonces which have hardened, crystallized, or debitumenized all the 
 older beds beneath, even to the Devonian, but, on the contrary, being even in its lowest 
 portions saturated with petroleum and containing deposits of All)ertite, — the study of this 
 formation, from whatever point of view, suggests conclusions of the greatest interest. So 
 marked and so wide-spread are the contrasts referred to, not in New Brunswick only but 
 everywhere around and over the Acadian basin, and so important were the movements by 
 which these contrasts were determined, that we may well style the ei)oeh in which they 
 occurred the Acadian or Devonian revolution. It was, indeed, probably at this time that 
 the Acadian basin proper first became clearly outlined l)y the ehn'ation of its bordering 
 hills, and when all the more marked of those physical features which now distinguish it 
 became determined. It is remarkable that ])oth the breadth of the formation and its 
 elevation above the sea-level progressively increase in passing from the western to the 
 eastern side of the Province, beds of this age in the former being rarely met with more 
 than two or throe hundred feet above the sea, and mostly confined to the valleys, while in 
 the opposite direction they gradually mount the sides of the hills, and, iu the case of 
 Shepody Mountain, in Albert, cap the latter at a height of twelve hundred feet. There 
 is, however, good reason to believe that they formerly spread over much wider areas and 
 possessed a considerably greater thickness than they now exhibit. Thixs, not only on 
 Shepody Mountain, but on other portions of the southern hills, at scarcely inferior eleva- 
 tions, strata of this age may be observed in positions which are not far from horizontal, 
 and which appear to be merely the detached and isolated fragments of a formation, 
 which at one time must have been (.'ontinuous, and which deeply buried the entire 
 region in which they are found. So again, similar rocks, showing similar evidences of 
 marine origin, are found in scattered areas over portions of York, Carleton and Victoria 
 Counties, which are also but little inclined, and which have probal)ly been disconnected 
 by erosion. Some of these in the Beccaquimic region cannot well be less than 800 or DOG 
 feet above the sea-level. In King's County the pecnliar topography of snc^h localities as 
 the Dut(;h valley and Upham, are evidently due to the removal of extensive masses of this 
 formation by denuding processes. 
 
 Still further evidence of the extent to which this formation has suffered by removal is 
 shown in its relations to the overlying coal-measures, and brings us to consider another 
 line of contact, of special interest as bearing upon the important question of the coal- 
 producing capacity of this formation. There can be no question that, at many points, the 
 
KlfOSION IN SOUTH KlfN AND (UNTRAIi NKW BItUNSWICK. 97 
 
 red I'lilcnroouH 1)o<1m of Ihc Tii^wcr ('nrltonircrnus puss up iiilo tlioH(» ol' tlu' millHloiic-irrit, 
 not only without iiiicoiiloiinily, Imt witli (lin'cl fviilfutt' ol' transition ln'twocii t lie two; as 
 lor uxiiniph' iil»otil llillHhoi'oujjh in Albert County, whort' the donudiition vvhieh has taken 
 place would appeur to have occurred at a later period: but on tho otlnir hand them are also 
 (nidenees that this coiiloiinity in in many instaneos only apparent, niNultiny; I'roni the Tact 
 thai holli sets ol' beds are api)roxiniiilely horizonhil, and that a lonsideraMe interval, 
 involviiijf a larji^e amount ol' corrosion and delbinialion ol' ihe surlace, occurred prior to 
 the deposition of the later strata. Thus, while in Ihe Ciraiid Laki^ district we have, on the 
 Nowcastlo River, a reyiilar and apparently conformable Hucccssion ol' Lower Carboniferous 
 marine sediments, millstoiui-grit, and productive coal-measures, all with only a very low 
 inclination ; borini^s throut^h these latter at a distance of only a few miles, and on the side 
 of the dippinji^ strnla, n'siiUed in showinu; Ihe entire absence of the lower beds, while at 
 yet another point, on Coal Creek, Ihe coal-mcasun^ rncks may be seen, for miles, resliniif 
 upon uplifted pre-Carboniferou8 slates, without the intervention of the Lower Carboni- 
 ferous. So also, in somo parts of York C(ninty, points almost within sij^ht of each other show 
 horizontal coal-measure rocks resting at one time upon nearly vertical Lower Silurian 
 beds and at another upon an ai)parently thick mass of Lower Carboniferous sedimeiils. 
 The wide-spread accumulations of dolerile, basalt and amygdaloid, which intervene 
 between the summit of Ihe last-named group and the n:illstone grit, may bo regarded as 
 further evidence of their unconformity. The supposition of conformity in beds so nearly 
 horizontal would necessarily imply, with wide superficial extent, u very limited thickness 
 to th(( coal-formation; while that last mentioned, by supposing the deposition of these 
 beds upon a surface extensively folded and eroded, w^ill at least admit of the possibility of 
 a very varied thickness of the coal strata, and consequently of the occurrence of other 
 seams of coal than those now known and worked near the surface. 
 
 The last contact to which it is necessary here to refer is that of the Carboniferous 
 formation with the Trias or new red-sandstone. Several examples of such contacts have 
 been observed along the southern coast, bul, apart from the fact of placing beyond question 
 the existence here of Mesozoic deposits, they present no features of spetdal interest. 
 
 In recapitulation, it will appear from the foregoing observations that we have in New 
 Brunswick not less than six well defined physical breaks, with all the usixal accompani- 
 ments of unconformity, viz., one between the Primordial and pre-Cambrian, four between 
 the several subdivisions of the Paleozoic, and one between the latter and the Mesozoic, 
 to which may be added ct-rtainly two, and probably three, similar breaks among the pre- 
 Cambrian rocks. In each of these cases, excepting perhaps that between the two main 
 divisions of the Carboniferoiis, the uucouformability is accompanied and in part indica- 
 ted by the formation of heavy beds of conglomerate, while, in most instances, the same 
 lines of junction are marked l)y the occurrence of eruptive rocks, the result probably of 
 the same forces to which the unconformity is to be ascril)ed. In the case of the Devonian 
 revolution, involving movements of the entire Paleozoic series, there wer(>, in addition to 
 the eruptions of trap, the extensive extravasations of granite which constitute so marked a 
 feature in the geology of Acadia, and which have had so profound an influence on all its 
 subsequent history. 
 
 Sec. IV., 1834. 13.