334 



ELIOT BLACKW ELDER 



its way down the slopes by rolling, slumping, and creeping. No 

 doubt these processes have all been in operation, at varying rates, 

 throughout the erosion history of the district. There is but little 

 recognizable evidence of them, however, relating to topographic 

 stages farther back than the Black Rock cycle of erosion. 



Fig. 48. — Talus glacier in a cirque on the north side of Sheep JNlountain, near the 

 head of Green River. 



The accumulations of talus arc greatest abo\e the timber-line, 

 and beneath the most resistant cliffrforming strata. In the lower 

 parts of glaciated valleys, the waste slopes have been largely swept 

 away, except in so far as the)' have begun to redcA'elop since the ice 

 disappeared. In a few cirques, talus glaciers, such as those described 

 by Cross and Howe' in the San Juan Mountains of Colorado, have 



' U.S. Gcol. Survey, Prof. Paper 6y, 1000. 



