PHYSIOGRAPHY OF THE BEAVERDELL MAP-AREA. 
5 
The oldest group, the Wallace, has been very extensively 
faulted, brecciated, and metamorphosed ; but only locally foliated. 
The metamorphism varies in character and intensity from 
place to place and is largely the result of later, batholithic 
intrusion. The West Fork batholith is also faulted, brecciated, 
and locally foliated but in less degree than the Wallace group. 
The Beaverdell batholith of the Eocene is nowhere foliated, sel- 
dom brecciated, and, except very locally, is unmetamorphosed. 
Both this batholith and the Curry series are faulted, and the 
Curry and Nipple Mountain series have been thrown into 
open folds. The folds in this area trend north and east of north ; 
the major faults and zones of brecciation are in groups striking 
from about north by west to northeast with a subordinate set 
trending east and west. Although there is a slight indication of 
regional foliation trending northwest, the areas underlain by 
rocks affected by it form a very small fraction of the whole. In 
all other areas of foliation the direction of strike corresponds to 
the line of contact of neighbouring intrusive masses. 
THE CANADIAN CORDILLERA. 
Between the forty-ninth and fifty-fifth parallels of latitude 
the Canadian Cordillera can be separated into three main divi- 
sions: a broad belt of mountains on the east, a more compact 
mountainous unit along the Pacific ocean on the west, and a lower 
and relatively flatter region between. The belt to the east con- 
sists of the Rocky Mountain system, the Purcell, the Selkirk, 
and the Columbia systems. The Rocky Mountain system trends 
north-northwest to northwest for about 1,000 miles. It is 
bounded on the east by the great plains and on the west by the 
Rocky Mountain trench, a narrow but persistent depression 
occupied in turn by many different streams. West of the 
Rocky Mountain system lie the Purcell range, the Selkirk system, 
and Columbia system. 1 
1 NameS and boundaries as given by R. A. Daly in “The nomenclature of 
the North American Cordillera between the 47th and 53rd parallels of latitude," 
The Geographic Journal, vol. 27, No. 6, June 1906, pp. 586-606, 1 map. 
