654 WILLIS T. LEE 



the head of the valley, is a beautiful example of the latter. It 

 rests behind a crescent shaped ridge — a comparatively recent 

 terminal moraine. Fragments of terminal moraines extending 

 partly across the valley bottom, occur in several places near the 

 head of the valley. 



Resume. — I. The exceptional amount of snow and ice in the 

 cirque at Mt. Arapahoe is due to the unusual advantages pre- 

 sented for its accumulation and preservation. These consist {a) 

 in trapping the drifting snow, and (b) in protecting it from sun 

 and warm winds. 2. Within the cirque are two fields of snow 

 and ice which are essentially independent of each other at the 

 present time. The larger field is estimated to be something like 

 two miles in width and about the same in length. 3. The snow 

 and ice of the larger field constitutes a glacier. This is attested 

 [a) by the amount of snow and ice there accumulated, and by 

 the inclination of its surface which varies from about 10° to 50 ; 

 (&) by its stratification indicated by the banding of the face ; 

 and (V) by its movement, indicated by the crevasses, the 

 moraines, and the rock flour. 4. This glacier is the survivor of 

 a much larger glacier which formally occupied the upper part of 

 Boulder Creek valley. 



Willis T. Lee. 



