No. 1.] DAWSON — GLACIATION OF BRITISH COLUMBIA. 33 



British Columbia may be described as including the whole 

 width of a certain portion of the Cordillera region of the con- 

 tinent. The Rocky Mountains, properly so called, form the 

 boundary between the belt of the Cordilleras and the great plains 

 to the east. The south-eastern flank of this system is defined 

 by a remarkably deep and straight valley, in which lie consider- 

 able portions of the courses of the largest rivers of the country. 

 Beyond this valley to the south-west, is a second and broader 

 mountain region, called by various names in different parts of 

 its length, but which may be designated as the Selkirk or 

 Gold Range. Many of the summits of these mountains are 

 scarcely less in altitude than these of the Rocky Mountains, 

 which frequently surpass 9000 feet. Nearly parallel to these 

 two great ranges is the Coast or Cascade Range, in which the 

 average altitude of the higher peaks may be stated as between 

 6000 and 7000 feet. A fourth range may be traced in a par- 

 tially submerged condition, in the mountains of Vancouver and 

 the Queen Charlotte Islands. Between the Coast Range and the 

 Selkirk or Gold Range lies the great Interior Plateau of British 

 Columbia. This represents the interior basin included between 

 the Sierra Nevada and Rocky Mountain ranges in better known 

 regions to the south. It has an average width of 100 miles, 

 and a mean elevation of about 3500 feet. Its height on the 

 whole increases to the south, while northward it falls gradually 

 towards the cluster of great lakes, and the low country of the 

 Peace River Valley. It is now dissected by deep and trough-like 

 river valleys, into most of which water standing at 3000 feet 

 above the present sea-level would penetrate; and though in some 

 places pretty level and uniform, it is generally when broadly 

 viewed only that its true character is apparent. The north- 

 western end of this plateau appears to be blocked by a hio-h 

 mountainous country formed by the coalescence of the three f>reat 

 ranges about latitude 55° 30'; while nearly coincident with the 

 49th parallel, is a second irregularly transverse mountainous zone 

 which is however traversed by several great river valleys, of 

 which that of the Okanagan in longitude 119" 30' is the most 

 important. 



The general conclusions arrived at as to the glacial phenomena 

 of the country as quoted from the paper above referred to are as 

 follows : — 

 V'OL. IX. • c JSIo. 1. 



