GLACIER PROBABLY TERMINATED ID STANDING WATER. 401 



Absence of Terminal Moraines near the Rocky Mountains. — The absence of 

 a terminal moraine at the extreme western limit of the till, near the foot of 

 the mountains, is a fact worthy of notice, especially in view of the fact that 

 the till of both the earlier and later glacial periods is found to extend 

 approximately the same distance westward, and that there is a narrow belt 

 from thirty to one hundred miles in width that would appear never to have 

 been covered by the ice-sheet. 



The most efficient reason that suggests itself to me to account for this state 

 of affairs is that the glacier terminated in one or more lakes, hemmed in 

 between the continental glacier and the mountains and cut off towards the 

 north and south by lateral glaciers flowing eastward in such valleys as those 

 of the Bow and North -Saskatchewan rivers. The morainic accumulation 

 would in that case be carried off either by icebergs or waves and currents 

 and spread out some distance beyond the limit of the till. This would 

 account for the presence of eastern erratics along the very foot of the 

 mountains, and may also account for the high terraces on the sides of such 

 valleys as that of the North Kootanie river. This condition could not, 

 however, have lasted for any great length of time, as no considerable amount 

 of stratified deposits are found in this unglaciated area. 



Western Pebbles. — The presence of western pebbles in the drift far out on 

 the plains was for a long time an almost insuperable barrier to the general 

 acceptance of the belief in its essentially eastern origin ; but the discovery 

 of large areas of Miocene conglomerates, holding these same pebbles, as far 

 east as long. 107° W., has almost entirely overcome this objection in furnish- 

 ing new centres of distribution from which these pebbles have been carried. 

 Still it is not improbable that some of the drift in the extreme western part 

 of the drift-covered country is derived from the mountains, having been 

 carried down by the local glaciers mentioned above. 



Direction of Ice Floiv. — In speaking of the general direction of flow of 

 the western portion of the great continental mer de glace it has been 

 customary to regard it as having advanced southwestward from the Archean 

 area — and certainly this was the direction of glacial motion when the ice 

 first reached the Winnipeg basin, — but recent investigations have shown 

 that in two cases, at all events, this direction was not sustained, viz., in the 

 great Winnipeg valley, and in the valley of the upper Assiniboiue, west of 

 the Duck and Riding mountains. In both these cases the direction of flow 

 was southward or southeastward in the direction of the trend of the valleys, 

 and parallel to the main axis of the Rocky Mountains. This direction was 

 in all probability sustained by the glacier all the way across the Canadian 

 plains, and we have thus one reason for its great extent, as the ice was moving 

 from a wide area of distribution to a much narrower area of dissipation, 

 and there would be a constant tendency to make up for the loss from the 

 surface by a crowding in from the sides. 



