420 PROCEEDINGS oF OTTAWA MEETING. 



where a \. MO E. direction, but when that river is reached these arc found to be 

 partly obliterated by a newer set coining from N. 50° E. This direction of the 

 newer set changes slow !v to N. 60° E. as the river is descended, the older set being 

 seen from time to time on favorably protected ruck surfaces. A remarkable feature 

 of the country to the northward of Lake Mistassini is the number of low hills 

 made up wholly of rounded bowlders. These lie parallel to the direction of the 

 stria' and culminate in sharp, narrow ridges that slope at high angles on either 

 side. These bowlder ridges are at times connected with rocky hills, but more often 

 stand up independently. 



On the Big, Great Whale and Clearwater rivers a similar condition of glaciation 

 is found, the direction of the stria' following the general slope of the country- 

 Along the Big river it is from N. 70° E. ; on the Great Whale from S. 70° E., and 

 alon.ii' the Clearwater from nearly due east, 



( )n the coast of Hudson hay the strife do not run in any one direction, but con- 

 form with local slopes. Here as many as four sets of striae have been observed on 

 the rocks ; any or all of these may mark the direction of local glaciers found toward 

 the close of the period on the rocky highlands facing the hay. 



The composition of the drift is largely local, hut bowlders from known localities 

 are at times found transported from fifty to one hundred miles from their original 

 sources. The limestones of .Mistassini are found over sixty miles to the south- 

 southwest of the nearest known bed. Bowlders of this limestone, along with 

 others of Huronian rocks, are not uncommon in the drift of the southern slope to 

 within a few miles of hake Saint John. As no areas of these rocks are known to 

 exist in the region south of the watershed, at some time, probably during the 

 period of greatest accumulation, the ice-cap must have moved up over the height 

 of land, carrying with it fragments of the rocks on the north side and scattered 

 them over the southern slope, where they are now found, over one hundred miles 

 from their known source. 



On a hill some 300 feet above Clearwater lake a bowlder of Silurian limestone 

 was found. Tins tends to prove the previously supposed presence of a basin of 

 rocks of this age in the level country south of Ungava hay, as the striae show 

 that the bowlder must have come from that direction. A chain of islands extends 

 up the eastern third of .lames hay. These are undoubtedly of glacial origin and 

 are the remains of a terminal moraine. Although they have been submerged at 

 or subsequent to their formation they still preserve all the characteristics of such 

 an origin, and the action during submergence has only slightly altered their ex- 

 ternal structure. They rise in their highest parts from 150 to 200 feet above the 

 present sea-level and are wholly composed of unstratified till. Their surface is 

 uneven, being dotted with small rounded lakes and ponds, while the hummocks 

 of bowlders have been flattened out and settled into compact masses by the later 

 wave action. Their faces are cut into terraces, hut there are no stratified deposits 

 anywhere. This moraine marked the limit of the glacier at a halt during the 

 period of retrocession and was not the limit during the time of greatest glaciation. 

 Then the ice pushed down from the interior of Labrador, crossed Hudsonbay 

 and passed up over the low country on the western and southwestern side, and 

 probably crossed the watershed and descended into Lake Superior. Of this we 

 have evidence, in the direction of the stria? and the presence of Silurian and 

 I tevonian limestone bowlders in the drifts, to show that this was 1 he direction of 

 the ice-flow, a Ion- the rivers falling into the southern ami southwestern portious 



