840 



N. M. FENNEMAN 



ice stream. In its more vigorous days, when it filled the valley 

 for some miles and was some hundreds of feet deeper than at 

 present, the inequalities of its bed must have been unable to 

 control the ice movement to any great extent, and therefore 

 failed to subdivide the glacier into a system of branching tribu- 



Fig. I. — Looking east, down the valley, from a point one-half mile below the 

 present terminus of the glacier. The shelf seen at the left is in the main rock terrace. 

 The lower and narrower valley suggests uplift and considerable erosion before the 

 glacier was developed. 



taries. It must then have appeared essentially as a single ice 

 stream. Indeed, its appearance, as viewed from the neighboring 

 mountains two years ago, 1 seems to have suggested but two 

 branches, separated by a moraine so low that a few extra yards 

 of depth would have rendered the whole a unit at the surface. 

 The valley bottom below the present terminus is barred with 

 crescent-shaped terminal moraines which mark the termini of 

 1 Willis T. Lee, loc. cit. 



