20 THE CANADIAN NATURALIST. [Vol. X. 



NOTE ON THE GEOLOGY OF THE PEACE RIVER 



REGION. 



By G. M. Dawson, D.S., A.R.S.M., F.G.S. 



(Abstract of paper read before the Natural History Society, Montreal, 



Feb. 28th, 1881.) 



Till 1875 we may be said to have known absolutely nothing 

 of the geology of the Peace River region. In that year, Mr. 

 Selwyn, the Director of the Geological Survey, starting from 

 McLeod's Lake in British Columbia, descended the Parsnip and 

 Peace Rivers to the confluence of the Smoky River, returning 

 by the same route. The geological notes published in the 

 report of the expedition have constituted the basis of subsequent 

 work. In 1879, it was determined to ascertain more completely 

 the character of the Peace and Pine River passes as railway 

 routes, and the prospective value of the Peace River basin. 

 The author of the paper was a member of the expedition of that 

 year, and the information obtained at this time, with that for- 

 merly alluded to, enables a clear general idea of the geological 

 features of the district to be formed. These are of interest as 

 representing the furthest northern portion of the interior conti- 

 nental region yet known with any precision, the country ex- 

 amined lying chiefly between the 54th and 57th parallels of north 

 latitude. 



The Rocky Mountain range is here narrow and comparatively 

 low, the higher peaks seldom exceeding 6,000 feet. It is chiefly 

 composed of limestone, in massive beds, in some of which fossils 

 of Devonian age have been found, the most abundant form being 

 Af7'i/2Ki reticularis, a shell widely spread in the Devonian rocks 

 of the Mackenzie district further north. The beds of the moun- 

 tains have general westerly dips, and overturned folds probably 

 occur. On the east side of the range, on both Peace and Pine 

 Rivers, hard dark calcareous beds are found holding Monotis 

 suhcircularis, a form characteristic of the " Alpine Trias " of 

 Nevada and California, and found also in several places on the 

 British Columbian coast. To the cast of these beds of the moun- 

 tains, and resting quite unconformably on them, are the Creta- 

 ceous rocks, which, between the mountains and eastern outcrop 



