92 G. M. DAWSON — ROCKY MOUNTAIN REGION IN CANADA 



(3) The recurrence of folding and disturbance parallel to the border 

 of the Pacific basin and the concurrent great changes in elevation of the 

 land relatively to the sea, both continued down to quite recent geolog- 

 ical times, the latter even into the Pleistocene. 



(4) The tremendous energy of denudation, in part due to the events 

 last referred to, but also dependent upon the position of the region on 

 the eastern border of a great ocean, where, in northern latitudes, an 

 excessive rainfall must have occurred at all periods on the seaward 

 mountain ranges. No comparable denuding forces were probably ever 

 operative on the east side of the continent in similar latitudes since the 

 definition of the ocean basins of the Pacific and Atlantic. 



