^, IMAGE EVALUATION TEST TARGET (MT-3) k A /^.^^ A ■^,,%' 4?, I/. 1.0 I.I 1^128 |2.5 ■50 ■^~ MlM U lili ^ as, 12.0 1.8 1.25 1.4 1 1.6 ^ 6" ► V] Vl > ^7). ^^j>r/ ^ > '/ s Photographic Sciences Corporation ^ V ^^ :\ \ ^.^ O^ '<<^/* ■«^' 23 WIST MAIN STRIET WEBSTER, N.Y. 14S80 (716) 873-4503 '^ <*) .^ ^J^ i/.. CIHM/ICMH Microfiche Series. CIHM/iCMH Collection de microfiches. Canadian Institute for Historical Microreproductions / Institut Canadian de microreproductions historiques Technical and Bibliographic Notet/Notas techniques et bibliographiques The Institute has attempted to obtain the best original copy available for filming. Features of this copy which may be bibliographical^y unique, which may alter any of the imeges In the reproduction, or which may significantly change the usual method of filming, are checked below. n n n n D y Coloured covers/ Couverture de couleur □ Covers damaged/ Couverture endommagie Covers restored and/or laminated/ Couverture restaur^ et/ou pellicuMe □ Cover title missing/ Le titre de couverture manque Coloured maps/ Cartes gtographiques en couleur □ Coloured inlc (i.e. other than blue or blacic)/ Encre de couleur (I.e. autre que bleue ou noire) I I Coloured plates and/or illustrations/ Planches et/ou illustrations en couleur Bound with other material/ ReliA avec d'autres documents Tight binding may cause shadows or distortion along interior margin/ La re liure serrie peut causer de I'ombre ou de la distortion le long de la marge inttrieure Blank leaves added during restoration may appear within the text. Whenever possible, these have been omitted from filming/ II se peut que certaines pages blanches ajouties lors d'une restauration apparaissent dans le texte, mais, lorsque cela Atait possible, ces pages n'ont pas 6t6 f ilm6es. Additional comments:/ Commentaires supplimentaires; L'Institut a microfilm* le meilleur exemplaire qu'il lui a At6 possible de se procurer. Les details de cet exemplaire qui sont peut-Atre uniques du point de vue bibliographique, qui peuvent modifier une image reproduite, ou qui peuvent exiger une modification dans la mithode normale de filmage sont indiquto ci-dessous. r~~| Coloured pages/ Pages de couleur Pages damaged/ Pages endommagies Pages restored and/oi Pages restauries et/ou pellicul6es Pages discoloured, stained or foxei Pages d6color6es, tachet^es ou piqu6es Pages detached/ Pages ditachdes Showthroughy Transparence Quality of prir Qualiti in(§gale de I'impression Includes supplementary materii Comprend du materiel supplimentaire Only edition available/ Seule Mition disponible I I Pages damaged/ I I Pages restored and/or laminated/ r~1 Pages discoloured, stained or foxed/ rri Pages detached/ fyj Showthrough/ I I Quality of print varies/ |~~1 Includes supplementary material/ I I Only edition available/ The c tothi Theh possi of th( filmin Orijir begin the la sion, other first p sion, or iilu Thelal shall TINUi which Maps, differ^ entire! beginr right fl requiri metho D Pages wholly or partially obscured by errata slips, tissues, etc., have been refilmed to ensure the best possible image/ Les pages totalement ou partlellement obscurcies par un feuillet d'errata, une pelure, etc., ont 6t6 filmies it nouveau de fapon it obtenir la meilleure image possible. Pagination M followi : 117-121 p. This item is filmed at the reduction ratio checked below/ Ce document est filmd au taux de reduction indiqu* ci-dessous. 10X 14X 18X 22X 26X 30X y • 12X 16X 20X a4X 2tX 32X ilaire s details ques du It modifier (iger une le f ilmage The copy filmed here has been reproduced thanks to the generosity of: National Library of Canada The Images appearing here are the best quality possible considering the condition and legibility of the original copy and in Iceeping with the filming contract specifications. L'exemplaire filmA fut reproduit grAce A la g^nArosit* de: Bibliothdque nationale du Canada Les Images suivantes ont iti reproduites avec le plus grand soin, compte tenu de la condition at de la nettetA de l'exemplaire filmA, et en conformity avec les conditions du contrat de filmage. 1/ udes Original copies in printed paper covers are filmed beginning with the front cover and ending on the last page with a printed or Illustrated impres- sion, or the back cover when appropriate. All other original copies are filmed beginning on the first page with a printed or illustrated impres- sion, and ending on the last page with a printed or illustrated impression. Les exemplalres orlginaux dont la couverture en papier est Imprimis sont fllmte en commen^ant par le premier plat et en terminant soit par la dernlAre page qui comporte une empreinte d'impression ou d'illustration, soit par le second plat, salon ie cas. Tous les autres exemplalres orlginaux sont film6s en commenpant par la premiere page qui comporte une empreinte d'impression ou d'illustration et en terminant par la derniAre page qui comporte une telle empreinte. The last recorded frame on each microfiche shall contain the symbol — »- (meaning "CON- TINUED"), or the symbol y (meaning "END"), whichever applies. Un des symboles suivants apparaftra sur la dernlAre image de cheque microfiche, selon le cas: le symbols — ► signifie "A SUIVRE", le symbols y signifie "FIN". lire Maps, plates, charts, etc.. may be. filmed at different reduction ratios. Those too large to be entirely included in one exposure are filmed beginning in the upper left hand corner, left to right and top to bottom, as many frames as required. The following diagrams illustrate the method: Les cartes, planches, tableaux, etc., peuvent Atre filmAs A des taux de rMuction diffirents. Lorsque ie document est trop grand pour Atre reproduit en un seul ciichi, il est fiimi A partir de Tangle supirieur gauche, de gauche A droite, et de haut en has, en prenant ie nombre d'images nicessaire. Les diagrammes suivants illustrent la mAthode. ly errata ed to mt me pelure, B^on A 1 2 3 32X 1 2 3 4 5 6 Section IV, 1890. [ 117 ] Trans. Rot. Soo. Canada. V. — The Evidence of a Nova Scotia Carhoni/erous Conglomerate. By E. Gilpin, Jb. (Read, May 28, 1890.) The records of the drift coverings of the province of Nova Scotia show, in many cases, clearly the source of their component pebbles, etc. The late Dr. Honeyman devoted much altention to this subject, and observed that the Triassic amygdaloids and traps of the Bay of Fundy have been carried across to the Atlantic equally with boulders of the Cobequid Mountain strata, on the north side of the Bay of Fundy, in Cumberland and Colchester counties, and boulders from the interA'oning carboniferous strata. The course of the flow has been, generally speaking, on a line running S. 20° E., and seems to have been in- fluenced by certain granitic masses protruding between the Cobequid Mountains and the Atlantic coast. The effect of this has been that in the vicinity of G-rand Lake, in Halifax County, the stream has become narrowed, and i'rom being wide spread in Hants and Col- chester counties has poured its boulders, etc., especially upon the district in the vicinity of Halifax. The drift lying south of the granitic ranges, referred to, is largely composed of granitic debris, until with distance the proportion of boulders from the underlying measures and from foreign sources predominated. Opposite openings in those granite ranges it was observed by Dr. Honeyman that on the southern side the predominance of granitic debris was not so decidedly marked. The Nictaux and La Have Rivers, in the western part of the province, appear in a similar manner to have marked another and parallel line of drift, as boulders from the Triassic measures of the North Mountain of Annapolis county have been observed at Lunenburg on the Atlantic coast. The consideration of the course and extent of these more modern accumulations, which are mentioned here on account of their importance in defining the route of a gigantic transporting agency, which has accumulated the material which will enter largely into the composition of future beds of beach shingle, to be under certain condi- tions consolidated into conglomerates of the future, may now be dropped. At numerous points on the shore large hills of drift are observable, presenting the process of being re- worked. Taking the end of one of these hills as it now stands on the edge of the Atlan- tic, and receives the rude assaults of its siirges^ it will be noticed that it is composed principally of the following materials, sand, clay, quartzite and slate boulders, more or less rounded, from the subjacent measures of th(> Lower Cambrian auriferous strata, of granitic boulders, of limestone and sandstone coarse and iine grained from the Carbonifer- ous, of amygdaloids and dolerite from the Trinssie, and a, greater or less but distinctly marked percentaye of syenitic, gneissic, porphyritic, etc., boulders finding their nearest known counterparts in the Col)c«|[uid Mountains. Under the encroachments of the ocean, 118 E. aiLPIN ON NOVA SCOTIA tho smaller coustituents, i.'ie gravel, sand, and clay, are ground down, and transported by the littoral currents into areas of deposition. This action causes a concentration of the boulders, and they are more directly acted on by the impact of the waves and their induced currents. The angular fragments are rounded or pulverised, and tho soft rounded boulders are reduced in size. The more compact and heavier boulders gradually bed them- selves, and are covered by lighter and smaller ones, while underneath all, on tho first compact and impervious layer that offers, of rock, or of hardindurated drift there is formed a layer composed of any magnetic iron ore grains, etc., that may have been present in the more highly metamorphic boulders. An examination therefore of a shingle beach on the Atlantic shore shows the source and the route of the .stones it is made up of, except in the case of the more friable ones which have oeeu destroyed in the rude democracy of the waves. In the ordinary geo- logical sequence it is assumed that this bed through some change in level or of current is buried beneath other sediments, that the infiltration of water charged with calcic car- bonate, silica, iron, etc , has bound the stones together, and produced a firm and compact mass. It may be mentioned here as a matter of fact, that the time involved in this last change may often be by no means as long as is assumed above. At several places on the shores of the province, brooks running out of swamps, or springs, in their passage over the beach stones, have deposited iron oxide which has acted as a cement. Similarly when a beach is formed against a shore whore few differing strata are met, or where the drift (Covering presents no evidence of having been enriched from foreign sources, it is uniform in the nature of the rocks composing it. The transportation in Cape Breton has been extremely local, and at the present day the drift mantle shows almost with certainty the nature of the underlying strata. Thus in the district surrounding the town of Sydney the drift is characterised by angular, irre- gular-shaped blocks of millstone grit and sandstone. The soil over the Carboniferous marine formation is more loamy, and less boukler-laden, the covering of the syenitic and felsitic series is scanty or wanting, and so on. This may be accounted for by the island not having been subjected to glacial action to the same extent as the mainland. This local facies of the modern drift in Cape Breton appears to be repeated in the car- boniferous and other conglomerates. The basal members of the Carboniferous in this island appear in many cases to have been deposited on exposed coast lines of the ancient shore of the Laurentiau and Lower Silurian strata, and to have filled the bays and valleys eroded in them during their immeasurably prolonged exposure to the elements. In the district lying at the eastern extremity of the St. Ann's Mountain, Victoria, Cape Breton, the conglomerates overlie the syenite. They are composed of angular and semi-rounded fragments of syenite, limestone, and quartzite evidertly derived from the measures immediately underlying them, and are red in color. Sandstone beds in the vicinity are observed to be made up entirely of the finer debris of the syenite. Mr. Fletcher, of the Canadian Geological Survey, describes the carboniferous conglo- merate of Watson's Brook, Cape Breton County, as : " Containing pebbles up to one foot in diameter, and comprises reddish porphyry, slaty felsite and quartzite, olive green compact hornblende rock, gray granite, argillite, banded sachyroidal compact and crystalline limestone, and serpentine. This conglomerate differs from that found higher up the brook in containing a larger number of pebbles 4)f rock 1 / i ^ CARBONIFEROUS CONGLOMBRAT K. 119 which do not oqcur iii tho Coxheath hills, but which have been derived I'rom strata simi- lar to those of George's Kiver and Kelly Cove." These foreign sources referred to by Mr. Fletcher hold beds referred to the Lower Silurian, and are situated a few miles to the north. Frequent allusions, which need not be enlarged upon here, will be found in his reports to similar compositions of conglomerates. Passing to Nova Scotia proper it is noticeable, referring again to the modern drift, that pre-carboniferous boulders are met at the mouth of Antigonish Harbour, which are evidently derived from the Arisaig district lying to the north on the strait of Northum- berland. The carboniferous conglomerates are like those of Cape Breton, largely if not almost exclusively composed of the material against which they rest, with an important exception to be noticed. On the southern side of the Cobequid Mountains, Sir William Dawson, in his Aca- dian Geology, page 251, speaks of the ancient sea of the beginning of the carboniferous period in the counties of Colchester and Hants, as irregular in shape and penetrating in long inlets, now river valleys, into the older metamorphic rocks to the eastward, and hav- VAg the Cobequids as its northern boundary. Thus on the Hanks of the Cobequids the lowest carboniferous beds consist of conglomerates, the stones and pebbles of which are identical with the rocks of the hills they are derived from, just as the materials of shingle beaches are derived from neighbouring cliiTs. There is another conglomerate in point, in Pictou County, known as the New Glas- gow conglomerate, from the name of the town which is partly built on it. This is com- posed almost exclusively of stones and pebbles from still lower carboniferous strata, and is described as follows by Sir William Logan, and Mr. Edward Hartley, in their report on the Pictou Coal Field, 'Geological Survey of Canada' Ileport, 1869-*73, page 63. " Coarse and fine conglomerate, with enclosed masses up to three feet in diameter. These are, with very few exceptions, derived from the rocks of the Millstone Grit, those of red sandstone and red shale predominating, while with them are all the green, greenish drab, chocolate brown, and mottled gray, and brownish sandstones, with calcareous no- dules. Nodular and other concretionary limestones have been recognised as forming part of the mass. The only other pebbles are of quart/ite and conglomerate derived from a mass of Devonian strata which protrudes through the conglomerate between the East and Middle Rivers." Along the east side of the Hants and Colchester county carboniferous district, and resting on pre-carboniferous quartzite and slate, are numerous beds of conglomerate. Owing to a recent discovery that the streams flowing over these conglomerates at Brook- field, eight miles south of Truro, and at two other points between Brookfield and Gay's River, lying about thirty miles south of Truro, yielded sights of gold, the writer's atten- tion has recently been turned to them. At Gay's River the occurrence of gold in these, conglomerates has long been known. At first it was believed that they were modern, but the geological position of the auriferous conglomerate as a member of the Lower or basal Carboniferous is assured. It was firtst examined by the late Professor F. C, Hartt, who determined its true geological position ; subsequently an examination was made by Dr. Honeyman who found the con- glomerate regularly overlain by limestone, gypsums, etc This view was confirmed by professional examinations of the district made by the writer some time after. This fact 120 '<}. (}ILPIN ON NOVA SCOTIA had an important bearing in tho question of mining, as the rocks wore much more com- pait than those of modern date would be. However, for some years mining operations were carried on to a small extent, and a lair knowledge; of the district, and of the aurifer- ous strata acquired. The following section taken at the mine will serve to show the composition ot the strata at the line of junction : — Loam and clay Variable thickness Layer of hardened and dark sand , to 1 inch Coarse sandstoiio 2 to 30 feet Conglomerate 10 to 20 feet Black sand and small pebbles 2 to 6 inches Auriferous pre-carboniferous slates. This section is exi)osed by a brook which has worn its way along the line of junction, and exposed the Carboniferous in a low cliff". They lie at an easy angle, dipping away from the older rocks, and rest directly on the auriferous slates which are nearly vertical, having an east and west course, and a southerly dip. The gold occixrs in the sand and in the lower part of the conglomerate, in flakes and plates, and minute grains, usually in the gravel filling the spaces between the larger boulders, but sometimes cemented directly on them. The slates have many seams a few inches in depth filled with sand and clay, and these crevices frequently carry gold. The top of the slate to a depth of a few inches, appeared at several points, to be filled with fine gold, which had so to speak, soaked into it. In mining, the greater part of the conglomerate, all the sand, and some of the slate was extracted and passed through a stamp mill. It was found necessary, ho\^ever, to reject many of the boulders as they were too hard to be readily crushed by th ? stamp mill, which was small and provided only with light stamps. These boulders were exam- ined, freed from any of the adhering cemented gravel, and thrown to one side. The official returns show an average yield to the ton of material crushed, of from 3 to 4 dwts., which was found but slightly remunerative on the scale of mining operations adopted. The rejected boulders amounted, as I am informed by those engaged in mining here, to about 20 per cent of the total volume of rock extracted. Among these boulders are recognisable many undistinguishable from those now forming part of the foreign in- gredients of the modern drift. There are to be seen diorite, porphyry, gneiss, calcareous sandstone, syenite, porphyrites, and granite, etc., apparently with as good a title to des- cent from the Cobequid Mountains as their more modern congeners. The rest of the con- glomerate is made up of boulders from the underlying slates and quartzites, grits and sandstones, apparently from the measures forming the headwaters of the Salmon River of Truro, and which may exist much nearer to Brookfield. The conglomerate lying north of the exposure at Gay's Kiver is traversed by brooks which have at places cut down into its lower portion, and in rearranging the detritus have brought small shows of gold within the reach of the prospector. These conglomerates resemble those of Gay's Eiver and are composed principally of boulders of the slates, etc., iipon which they rest. Search, however, shows in them a considerable percentage of the older erratics corresponding to those referr(>d to in speakiiig of the Gay's IJiver conglomerate. The next step is the consideration of the conglomerates of the south lude of the Cobe- I CARBONIPBEOUS CONf}LOMERATB. 121 quids, which, as already referred to, present pebbles derived from the hills they rest on ; and of the New Grlasgow conglomerate presenting a similar agglomeration obviously from a source close at hand. The position of the carboniferous conglomerates lying on the south flank of the Cobe- quid Mountains presumably favoured their being composed solely from them ; the distance of the New Glasgow conglomerate from any source of admixture to the north presumably gave it its distinctive character. If then in a district lying some distance to the south, both of the Oobequids and of the measures lying immediately south of the New Grlasgow conglomerate, a beach deposit occurs having, in addition to its proper and immediate derivative component parts, a con- siderable percentage of foreign drift boulders it may be presumably inferred that at a date previous to its formation, erosive, denuding, and transporting facilities existed, whose aid may require to be invoked to account for this admixture in a deposit which, as shown, would under ordinary circumstances have been exp'^cted to be normal, i. e.. composed exclusively of local material. If the Gray's River conglomerate had added to it triassic, and carboniferous pebbles it would pass as a modern drift or beach, if regarded from the standpoint of its composition without reference to its position as a member of the lower carboniferous horizon. Taking away from a modern drift or beach the triassic and the carboniferous boulders and pebbles, there remains the substance of a Brookfield conglomerate, formed at the base of the Car- boniferous and presenting a parallel facios, suggesting similar operations of nature as preliminary to its aggregation. i yec. IV, 1800. 16.