NO. I FORMATIONS OF BEAVERFOOT-BRISCQ-STANFORD RANGE 47 



true Upper Cambrian fauna is found beneath the massive Lyell hme- 

 stone and not above it in all sections north of Bow River Valley in 

 Alberta. The supposed equivalent of the Lyell limestone has not been 

 seen on the western side or projecting- from beneath the floor of the 

 Columbia River Valley. 



East of Golden in Kicking Horse Canyon the lower Mons shales 

 and interbedded limestones are folded, faulted and upturned for about 

 3.5 miles (5.6 km.) to where a fault brings them in contact with the 

 graptolite shales of the Glenogle ? formation. Fossils were found 

 in a hurried trip up the Canyon at two zones in the lower Mons. 



In the upper, eastern end of Sinclair Canyon the orderly succession 

 from the upper Mons through the lower Ordovician Sinclair graptolite 

 beds to the Wonah Ouartzite at the base of the Silurian is preserved ; 

 the Glenogle shales have not been identified. (See note on pp. 32-34.) 



Conclusion. — From the present position of the pre-Devonian for- 

 mations in the Beaverfoot-Brisco-Stanford Range and their remnants 

 in the Columbia River Valley from Beavermouth to Canal Flats, it is 

 quite probable that all of the formations extended westward over the 

 area now occupied by the Columbia River Valley and thinned out 

 against a pi-e-Cambrian land area now included in the Dogtooth and 

 Purcell IMountains. 



NEW FORMATION NAMES 



silurian 



Brisco Formation 



Locality. — Upper southwest slope of Sinclair Mountain south of 

 Sinclair Pass and along the western clififs of the Brisco-Beaverfoot- 

 Stanford Range facing the Columbia River Valley, British Columbia, 

 Canada. 



Derivation. — From Brisco Range. 



Character. — Dark, rough weathering, finely arenaceous and mag- 

 nesian limestones. Band of black argillaceous graptolite-bearing rock 

 1 00 -I- feet (30.4-I- m.) thick. 



Thickness. — Estimated at 1,200 feet (365.8 m.) on Sinclair Moun- 

 tain, but probably it will be found to be thicker when the upper limits 

 of the formation are determined. 



Organic remains.- — Brachiopods and graptolites of Silurian age. 

 (Lists on pp. 11-13.) 



Observations. — During the field season of 1923, Dr. Edwin Kirk 

 of the U. S. Geological Survey accompanied me in the field and made 

 a detailed study of the Silurian limestones of the Brisco and Stan- 

 ford Ranges, which are the southern continuation of the Beaverfoot 



