Extracts from reports on the district of Ungava, recently added to the province of Quebec under the name of the territory of New Quebec . have greatly affected these clasticrocks, changing them into gneisses and schists, so that for a considerable dis-tance from the contact, they resemble lithologically, the Grenville series of theLaurentian. The granites appear not only to have produced the schistosity, butto have caused infiltrations of heated waters carrying silica aind silicates in so-lution depositing large quantities of quartz and felspar between the laminae ofthe mica and hornblende-sch
Extracts from reports on the district of Ungava, recently added to the province of Quebec under the name of the territory of New Quebec . have greatly affected these clasticrocks, changing them into gneisses and schists, so that for a considerable dis-tance from the contact, they resemble lithologically, the Grenville series of theLaurentian. The granites appear not only to have produced the schistosity, butto have caused infiltrations of heated waters carrying silica aind silicates in so-lution depositing large quantities of quartz and felspar between the laminae ofthe mica and hornblende-schists, changing these into typical gneisses, which, aswell as the schists, usually carry large quantities of garnet often in very largecrystals. When associated with gabbros, diabases and their decomposition-products, the bedded rocks are often ramified with quartz veins, generally hold-ing considerable pyrite, these veins are most abundant near contacts with newergranites. Several samples from such veins have been assayed for gold with ne-gative results, but as already explained, these cannot be accepted as in anysense GEOLOGY AND ECONOMIC MINERALS OF CANADA I97 EXTRACTS FROM GEOLOGY AND ECONOMIC MINERALS OF CANADA By G. A. YOUNG. THE LAURENTIAN PLATEAU GEOLOGY. The Laurentian Plateau reg-ion, surrounding Hudson bay with a U-shapedform, has an area of over 2,000,000 square miles. Limited in the east by theNorth Atlantic and by the gulf and estuary of the St. Lawrence as far as the cityof Quebec, its southern boundary there passes inland and up the Ottawa river tobeyond the city of Ottawa, then turns abruptly to the south and crosses the In-ternational Boundary at Brockville. Farther west, at the foot of Lake Ontario,it crosses back into Canada and follows a nearly due east and west line to thefoot of Georgian bay, from which point the two upper Great lakes form thebounding line. West of Lake Superior the Laurentian Plateau region extendssouth into the United States
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