122 A. C. SPENCER — PACIFIC MOUNTAIN SYSTEM 



Dr C. W. Hayes in describing the Coast range says : ^ 



"Throughout its entire extent, but particularly in its northern portion, the 

 Coast range does not possess a distinct crest line, but is a rather narrow belt of 

 dissected plateau. The breadth of the belt is nearly 40 miles, though the eastern 

 margin, where it merges with the interior plateau, is not well defined." 



The character of the southern portion of the Coast range, as viewed 

 from the eastern summits of the range, is described by Dr G. M. Da-wson 

 in the following words : t 



" From an elevated point of view it will be observed that a large number of the 

 mountain masses of the range approximate in height to 8,000 feet, while a few 

 onh' reach or slightly surpass 9,000 feet; that there are few instances of really 

 dominant summits with lesser subsidiary mountains grouped around them, but 

 that in widely extended views to the south, west, or north the very numerous and 

 closely set sharp summits run together to form a jagged, but in the main nearly 

 level, horizon line." 



In each of these descriptions, excepting the last, the authors leave 

 room for the origin of the plateau feature by subaerial erosion of the 

 land, and in the case of the first two this origin is the one assigned. Doc- 

 tor Dawson, however, specifically excludes the process of baseleveling in 

 the following words : 



"The uniformity in height of the culminating points and ridges of the Coast 

 range can have little, if any, connection with the original form and height of the 

 elevated tract of the earth's crust out of which the existing ranges have been 

 carved by a prolonged process of denudation." 



This opinion of the distinguished Canadian scientist and the alterna- 

 tive hypothesis which he develops J [to replace the theor\^ of baseleveling 

 as an explanation of the features described both seem unwarranted to 

 the present writer, who believes that all of the plateau features which 

 are described in the foregoing paragraphs are representative of former 

 peneplains which have been elevated far above their original position. 



Interior and Yukon Plateaus 



The Interior and Yukon plateaus have been described by Dawson, 

 Hayes, and Spurr. In British Columbia the relativel}^ depressed belt 



*The Yukon District. Jour. School Geography, vol. i, 1897, p. 237. See also Expedition through 

 the Yukon District. National Geographic Magazine, vol. iv, 1892, pp. 128-162. 



•} Report on the Kamloops map-sheet, British Columbia, Geol. Survey Canada, Ann. Report for 

 1895, p. 10 B. 



I The reader who is not familiar with the hypothesis referred to for explaining the existence of 

 summits of uniform elevation in regions of high altitude will be interested to consult the portion 

 of Doctor Dawson's paper which immediately follows the above quotation. 



