[schofield] rocky MOUNTAIN TRENCH 65 



flock from Colville and other places, is without doubt, the continuation 

 of the same great natural feature. It is the beUef that this valley is 

 continued to the north, following the course of Canoe River, that 

 makes me so sanguine that by this route a passage could be effected 

 into the valleys of either Thompson or Fraser River. "^ — A surmise 

 which was entirely justified. 



These men were explorers in a geographical sense, and although 

 their travels added greatly to the knowledge of the Cordillera, yet, 

 with the exception of Hector of Palliser's expedition, they made very 

 few geological observations. 



General Geological Features 



The rock formations exposed in the immediate vicinity of the 

 trench embrace a wide range from the oldest known rocks in British 

 Columbia to the most recent. The following table presents these 

 formations in a broad way: 



Cenozoic Recent Gravels and sands. 



Pleistocene Drift, fluvioglacial deposits. 



Tertiary Miocene Sandstones, shales, and volcanic rocks. 



Laramie Sandstone and shales. 



Mesozoic 



Palaeozoic Carboniferous Limestones and shales. 



Devonian Limestones and shales. 



Silurian 



Ordovician Limestone shales. 



Cambrian Limestone shales. 



Pre-Cambrian . . . .Beltian Quartzites, argillites. 



Shuswap series Mica schists, limestones, and quartzites. 



Shuswap Series 



The Shuswap series which outcrops along the great valley consists 

 of mica schists, altered limestones, gneiss, and intrusions of granite. 

 These rocks are remarkable for their constant lithological characters 

 throughout their wide distribution from the International Boundary 



^ "Further papers relative to the Exploration by the expedition under Captain 

 Palliser, of that portion of British North America which lies between the northern 

 branch of the river Saskatchewan and the Frontier, and between the Red River and 

 the Rocky Mountains and thence to the Pacific Ocean." Presented to both Houses 

 of Parliament by command of Her Majesty, 1860. 



i-ec. 1\', Sig. 5 



