

low.] JAMES' BAY. 47 J 



hills trends from the lake towards the north-east, and forms a 

 distinct wall to the wide, flat plains through which the Big River 

 flows. 



Above the lake the river has cut out a shallow channel through de- stratified sand 



° clays. 



posits of non-fossiliferous stratified sands and clays, which on the lower 

 reaches sometimes show cut faces of pure sand, occasionally overlying 

 thin deposits of clay without boulders. Beyond the river valley the 

 country is almost flat, with a few isolated ridges of gneiss rising from 

 fifty to one hundred and fifty feet above (he general surface. At the 

 chutes and rapids these ridges cross the river. 



Above the upper chute the river approaches the high rocky land on Terraces, 

 the north, along the base of which are two terraces rising twenty and 

 fifty feet above the present river level. Where examined they were 

 found to present faces of stratified sand and fine gravel in many places 

 overlying beds of fine blue clay. Above Kawachiwan River the hills 

 also approach the river from the south, and along their base similar 

 terraces rise ten, thirty and fifty feet above the river. 



The deposits in which these terraces have been cut are of fluviatile 

 or lacustrine origin. The river at the close of the glacial period was 

 probably dammed in various places with drift barriers which caused 

 it to cover the wide flat valley between the higher rocky hills with 

 lake areas in which the clays, sands and gravels were deposited. 



Where the terraces are close to the higher rocky hills, their surface 

 and faces are strewn with boulders evidently rolled down from the 

 higher elevations where they thickly cover the rocky surface; at points 

 distant from the hills no boulders were observed on the terraces. 



Along the river valley and on the islands, the trees are chiefly blackTimber. 

 and white spruce and tamarac, with some balsam poplar and balsam 

 spruce. Many of these trees are eighteen inches in diameter, three 

 feet from the ground. On the higher parts out of the river valley the 

 trees are smaller, and are black spruce, banksian pine and tamarac. 



The country composing the river plain is generally swampy. Just 

 above the delta of Shatachewan Lake, on the south bank, is an exposure 

 of coarse, grey, garnetiferous hornblende-gneiss, penetrated by numer- 

 ous veins of pure red orthoclase. Strike N. 4*7° E. 



At the first rapid above, the rock is a fine-grained grey mica-gneiss, Rocks, 

 followed by coarse-grain ed, grey hornblendic-gneiss, holding porphyr- 

 itic crystals of pale-pink orthoclase. 



At the ten-foot chute is a very coarse-grained grey gneiss, with well 

 developed crystals of hornblende and orthoclase ; along with it are 

 small bands of fine-grained, pink, orthoclase-hornblcnde-gneiss, pene- 

 trated by many large veins of quartz and orthoclase, holding red gar- 

 net and black tourmaline crystals. The bedding of theso rocks is 



