NO. I FORMATIONS OF BEAVERFOOT-BRISCO-STANFORD RANGE 3 



INTRODUCTION 



Late in the field season of 1922, 1 made a rapid reconnaissance along 

 Sinclair Canyon from the Pass at its head on the crest of the Brisco- 

 Stanford Range to the mouth of the canyon where it opens out on 

 the east side of the Columbia River Valley, and during the field 

 season of 1923 I studied more in detail the Sinclair section, and to 

 the south the Stoddart-Dry Creek, the Fairmount and Canal Flats 

 sections of the Stanford Range, and to the north the Vermilion and 

 Harrogate sections of the Brisco Range, and the Kicking Horse 

 Canyon section at the northern end of the Beaverfoot Range. I was 

 accompanied by Dr. Edwin Kirk, of the United States Geological 

 Survey, who studied the Upper Ordovician and Silurian formations, 

 and Mrs. Walcott, who collected many Ozarkian and Cambrian 

 fossils. 



The three ranges grouped in the title are practically one continuous 

 range on the eastern side of the Columbia River Valley that were 

 given local names by the early settlers and surveyors. They are all 

 more or less capped by the upturned hard, silicious, magnesian 

 Silurian limestones that have resisted the agencies of erosion and now 

 form high clifir's, sharp ridges and peaks, while the more readily 

 disintegrated shales and thin-bedded limestones of the Ordovician, 

 Ozarkian and Cambrian beneath have been deeply eroded since the 

 close of Jurassic time.' On the west the great " Rocky Mountain 

 Trench " developed, and on the east the deep valley of the Kootenay- 

 Beaverfoot Rivers. Nearly all of the Devonian limestones and shales 

 and Carboniferous limestones of pre-Jurassic time that may have 

 been superjacent to the Silurian over the area between the Rocky 

 Mountain Continental Divide and the Selkirk Mountains in British 

 Columbia south of the main line of the Canadian Pacific Railway 

 have disappeared in the millions of years since they were first sub- 

 jected to erosion." 



For many years I wished to know more of the formations of the 

 western ridges of the main range of the Rocky Mountains facing the 

 Columbia River Valley, and I was delighted when the papers of Allan,' 

 Schofield,^ and Shepard " appeared with a more or less detailed 



^ Schofield, Trans. Roy. Soc. Canada, 3d Ser., Vol. 14, Sec. IV, 1921, pp. 90-97. 



^ In this connection the student should read Prof. S. J. Schofield's admirable 

 paper on the " Origin of the Rocky Mountain Trench," loc. cit., pp. 61-97. 



' Allan, John A., Report Can. Geol. Surv. for 1912, Memoir Geol. Surv. 

 Canada, No. 55, 1914, Geol. Ser. No. 46, pp. 94-102. 



' Schofield, Stuart J., Trans. Roy. Soc. Canada, 3d Ser., Vol. 14, Sec. IV, 

 1920, pp. 61-86; Geol. Surv. Canada. Bull. 35, 1922, Geol. Ser. No. 42, pp. 1-15. 



® Shepard, Francis P., Jour. Geol, Vol. 30, pp. 77-8i, 89-99, 361-376. 



