SOME SUBORDINATE RIDGES 127 



to explain every even sky-line or approximate uniformity in heights of moun- 

 tain summits, while every peculiarity in drainage is accounted for as an inherit- 

 ance from a past cycle of erosion, overlooking in many cases a simpler 

 explanation involving only "processes now in operation"; he wonders if 

 there does not lurk therein somewhat of the old catastrophism. 



The writer's thanks are due to Professors Davis and Hopkins 

 for valuable criticism and suggestion in preparing this paper. 



