[schofield] rocky MOUNTAIN TRENCH 85 



"Deserters' Canon has the appearance of a recent channel, and 

 probably owes its origin to an alteration in the course of the stream 

 during the glacial period, as the easily eroded material of which its 

 banks are formed could not have withstood the assaults of a large, 

 swift stream heavily charged with sediment, such as the Finlay, for 

 any lengthened period. 



"The Tertiary conglomerates and associated rocks are replaced, 

 a short distance east of the Deserters' Canon, by the gneisses and the 

 mica-schists of the Shuswap series, but extend in a westerly direction 

 for four or five miles, or as far as the base of the mountain range 

 bounding the valley in this direction. 



"Above the Deserters' Canon, the valley is bordered on the west 

 by a conspicuous range of white mountains from 2,000 to 3,000 feet in 

 height. On closer examination these proved to be composed of a 

 fine-grained, whitish, compact limestone. This rock weathers in 

 places to a light yellow or rusty colour, and occasionally is very siliceous. 

 No fossils are found in it, but from its position relatively to the 

 Shuswap series, it was referred to the Cambrian. The limestone is 

 very much disturbed and probably lies along a line of faulting running 

 with the valley. 



"The schists and gneisses of the Shuswap series form the border- 

 ing mountain ranges on both sides of the Finlay below the mouth of 

 the Ingenica, but above that point, while still continuing on the east, 

 they recede toward the west, and are replaced by the limestones 

 referred to above. 



"From Deserters' Canon to Paul's Branch, a distance of thirty 

 miles in a straight line, the Finlay winds through the centre of its 

 valley without touching the bordering mountain ranges. The valley 

 in this stretch is floored throughout with Laramie conglomerates, 

 sandstones, and shales, exposures of which occur at intervals all along. 

 These rocks, here, are little indurated and occasionally hold small 

 lignite seams. Fossil plants occur in many of the beds. 



"Ten miles below Paul's Branch, banks of glacial deposits 225 

 feet high occur at the bends of the stream. The banks are sloping 

 below, but are capped with steep blufifs above, consisting mostly of 

 coarsely stratified gravels interbedded with bands of hard boulder- 

 clay filled with scratched boulders. The boulder-clay bands often 

 pass into gravels when traced along their outcrop. 



"At Paul's Branch, the river approaches the mountains on the 

 east, and an opportunity was afforded for a short trip inland. Paul's 

 Branch enters the Finlay through a deep narrow cafion, cut through 

 the hard rocks of the outer range. Farther back, its valley becomes 



