CREST LINES IN THE HIGH SIERRAS 



'587 



continuous cliff, running with moderate undulation parallel to the 

 ridge axis. 



I have no photograph representing this topographic type in its 

 purity. Fig. 7, exhibiting a ridge of greater altitude, serves to show 

 a somewhat similar chff, wrought by glacial head-erosion but imper- 

 fectly divided into cirques, and culminating in a crest from which 

 nonglacial profiles descend in the opposite direction. But the example 



Fig. 7. — Westward from Mount Hoffmann, Sierra Nevada. Compare the glacial 

 topography of the north (right) face of ridge, with the nonglacial' profiles toward the 

 south. [Photograph by A. C. Lawson.] 



differs from the type in the stronger expression of the ice-work, in 

 the comparatively high grade of the nonglacial profiles, and in the 

 fact that those profiles, as seen in the photograph, conceal south- 

 facing cirques of some magnitude. 



The asymmetry of these lower ridges is more pronounced than 

 that of any others, because instead of contrasting two phases of 

 glacial erosion they contrast glacial with nonglacial. It is worthy 

 of note also, though not strictly germane to my subject, that the 

 contrast in sculpture of the two ridge slopes serves to compare the 

 efficiency of subaerial degradation with that of one phase of glacial 



