Epidote and Calcite

f • vffiiM t&h o..,;,.,.'.;;:: jâ;. ÂMSS H !^& • DEPOSITED BY THE COMMITTEE ON (Braouate Stuoics. *•*-+•*-*•*****>*> No. Library of PIoEill Uniuersity MONTREAL Received GEOLOGY OP AN AKEA IN THE VICINITY OP GULL AND OLGA LAKES, NORTHWESTERN QUEBEC, JteOIU. UNIVERSITY. APRIL 1913. A,O.DUPRESNE. During the summer of 1912, Dr J.A.Bancroft, Associate Professor of Geology at McGill University ,was instructed by the Quebec Department of Mines to make a geological reconnaissance of the District ^lorth of Transcontinental Railway in North Western Quebec. Having been fortunate enough to accompany Dr Bancroft as assistant ,1 submit,in this paper,the results of a geological examination of the 80untry surrounding Gull & Olga Lakes,of which I made an independent investigation. LOCATION. The district is situated on the James Bay side of the Height of Land, about mid-way between the Transcontinental and James Bay,one hundred and ten miles east of the Quebec-Ontario boundry. The accompanying key-map shows the relative position of the area. It lies between 76 fi 30' and 77- 30f West Longitude and 49-A50*North Latitude. The district has an area of about five hundred square miles. MEANS OP ACCESS, a) The district is best reached by way of The Grand JLJ^ Trunk Pacific,starting from Cochrane -Bast and going to the A Natagagan River or the Bell River. The rest of the journey can be made by^ going down either of these rivers to Ma t*a garni A Lake which is situated just west of the district under conside rs ration and is connected with Olga Lake by a River five miles long? This route is certainly very easy and diligent canoemen, leaving the railroad at either point; could reach the discharge of - 2 - of Bell River in four days. b) Prom James Bay,either up the Nottaway River to Mattagami Lake or the Rupert or Broadback Rivers/passing through Lake Evans to Gull Lake. People who had travelled through that part of the country claimed the last named river to be preferable. c) Prom Lake St John ,by way of Chibougaman Route going west by the Obatogamafc River. But this is a very long and difficult journey which should not be contemplated except by people travelling for excitement. In 1895 Bell followed an altogether different route the following being a description taken from the Annual Report, Vol.VIII 1895,ofAGeological Survey of Canada: " In going northward by canoe from Maniwaki,on the Gatineau River,two routes are available ,one by the Gatineau River and its tributory the Gens de Terre and the other by the Desert and its branch the Thomasine. Both are eery difficult for loaded canoes. We left Maniwaki village on the 1st of July and followed the Desert route to Lac des Rapides. This lake has two outlets ,one southward to the Gatineau,and the other northward discharging part of its water into the Upper Ottawa at a pl?ce called " The Barriere"or Dam. From this locality we followed the Ottawa downstream or westward to Grand Lake". Prom this place Bell crossed the Height of Land and went down the Bell River continuing the journey as in(a). Our expedition reached Mattagami Lake by passing down the Harricanaw River and crossing to Aiiard River over a four and half mile portage in Xuskeg. - 3 - PREVIOUS WORK* In the summers of 1895 and 1896,Bell made a geological reconnaissance of a large tract of country in Northwestern Quebec lying between the Rupert River on the $orth,the Upper part of the Ottawa Hiver on the south ,Jlistassini Lake on the east and the Quebec-Ontario boundary on the >»est« The results of his explorations are contained in the yearly reports of 1895 and 1896 and also in Part K of the Annual Report of 1900,volume XIII. Surveys were conducted by Henry 0*Sullivan on be-half of the Department of Crown Lands of Quebec in the years of 1897 and 1898. GENERAL DESCRIPTION OT THE REGION. Gull and Olga Lakes,owing situated in the center of S what was called by 4uess the n Canadian Shield" are surrounded by typical Laurenti^n country. It is *?. flat or slightly undulating plateau with rounded hills in the south and south-eastern part of the area. These hills do not reach a greater elevation than 500 above the level of Gull Lake . They have received the name of Dalhousie mountains and by the Waswanipi Indirns;are called the Sasegawetchew Mountain During a period of intense glaciation ,which was general in Pleistocene times all over Eastern Canada and the Eastern United States ,the country was profoundly eroded producing a smooth gently rolling surface which is now covered by the debris left by the retreating ice-sheet^ and the accumulation of strati fied sands and clays .containing boulders deposited probably in a glacial lake. - 4 - The general level of the country is about thirty feet above the surface of the lakes. Mattagami,Olga 8c Gull Lakes are resoectively 616,635,660 feet above the level of James Bay. Gull and Olga lakes form large bodies of water ,the 4 first of which is the larger possessing a roughly elliptical shape with am approximate length of fifteen miles and a width of nine miles . A remarkable feature is the o-û^^dsaace of boul ders which are strewn on the shores of this lake. One receives the impression of an artificial lake ,the shores of which have been paved with boulders a large percentage of which are granite. At the heads of the bays sandy beaches have developed. Many of the islands in the lake are nothing but accumu~ lations of-boulders ,some being of the Drumlin type. L Eskers were noticed on the northern and pastern shores of the lake, some consisting of gravel and sand,others of large boulders of granite and greenstone. It is most probable that the level of the water in this lake was once much higher than to-day for beaches,in many places extending as far as sixty paces from the actual shore line,may be seen. The upper part of the boulder beach is foundf to be covered with a thick layer of moss "bjcackenêeds and even in some cases by trees. Gull Lake is the meeting point of two large rivers draining a considerable portion of the country lying to the $ast and north of the area described in this report. Of these the Waswanipi receives the water of Lake Chibougamam ,Qbatagomaia and adjacent lakes ,the other receiving the waters of more or A less unknown area between Waswanipi & Rupert Rivers. - 5 - Olga Lake which extends in a ôrth Easterly direction, having a length ofl some twelve miles and average width of four miles . Deep bays are seen ortfcsits Eastern side following *^ approximatfcyely the direction of strike of the Keewatin Schist. Thw lake is separated in two parts by a narrow sand bar ,the result of the washing of a gravel and sand hill on the north west side of the narrows ; The southern half of Olga Lake is very shallow and muddy,its water assuming a light brown colour on a windy day. Anywhere in Elizabeth Bay the bottom can be reached with the paddle. Very little rock is exposed along the shore of Gull Lake,while around Olga Lake long stretches of shore are rocky. It is quite remarkable that the southern shores of these lakes show much more numerous outcrops of rock than elsewhere. This agrees with conditions found in other areas of northwestern Quebec. ( Rapport on the Geology and Mineral Resour- ces of LakesKewagama$AKeekeek Re ;ion,Quebec^Bureau of Liines,I9II.) ESKERS. On the north shore of Gull Lake, at the narrows between Lower and Iliddle Gull Lakes,below the little islands marked on Dr Bell's map, a. long narrow ridge formed by glacial detritus was examined , This esker extending towards 20- E is about fifty feet above the level of the lake . Under every upturned tree growing on the esker,boulders,pebbles and sand could be seen Along the ijast shore on the prolongation of the line of the previous esker, long rid-res, probably of the same type oiff deposit were hot iced . Many of the islands and different parts of the )*j*6*» shore especially on the west side of Gull Lakes,are of the same nature. On the north shore of Gull Lake west of the first esker described,an elliptical accumulation of boulders and sand of a height of 70 feet, covered with Jack Pines , is probably a " Kame M as is also the high bank of gravel and sand at the •sera?* narrows in the center of Olga Lake ,which is responsible for the sand barreltting the lake in two, DRUMLINS. In the center of Gull Lake, a small island is formed on its north side by the bold face of a granite exposure while the south side consists of large angular blocks of granite, weighing many tons ,which have been piled up and form a very typical drumlin such as has been described by Dr Barlow in his report of the Chibougaman district: n The irregular accumula tions of boulders with very little of the finer interstitial matter ( gravel and sand ) have a rather definite elongated outline ,with their longer axis in the direction of the ice ( ) movement,A The origin of these drumlins is still a matter of doubt and dispute and opinion seems divided as to whether a) they were accumulated beneath the ice under special condi tions without the agency of water or (b) that they were deve loped by erosion of pre-existing drift material ", ( Dr Barlow and others t-Rwport on the Geology and Mineral Resources of the Chibougaman Region, P.P.130;) The three rivers discharging Waswanipi,Gull and Olga la kes are swift.

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