202 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



across on a northeast-southwest Hne passing through Kicking Horse 

 Pass, and about 65 miles (104.6 km.) on a Hne passing through 

 Banff in the Bow Valley. The north and south axis extends from 

 Crowsnest Pass to the headwaters of the Saskatchewan River, about 

 225 miles (362 km.). 



There has been little compression of the strata and shortening of 

 the northwest-southeast axis but the pressure from the southwest 

 has flexed, faulted, and upturned the strata to such an extent as to 

 materially shorten the northeast-southwest axis and narrow the area 

 originally occupied by the pre-Devonian sediments in this region. 

 This is illustrated b}^ the sections of McConnell ' and Allan ^ which 

 cross the Rocky Mountains on the line of the Bow Valley and Kicking 

 Horse Pass and River, also by the sections of the Cascade Coal Basin 

 by Dowling ' and photographs of the upturned strata of the Sawback 

 Range in this paper (pis. 30, 31). The shortening of the transverse 

 axis and consequent narrowing of the area on this line is estimated to 

 ])e about 25 per cent, which leads to the conclusion that its original 

 width was about 96 miles (154.5 km.). On the south the sea nar- 

 rowed to where, near Kootenay Pass, the pre-Cambrian land area of 

 Kintla Island appears to have cut it off on the east and south as far 

 as Marias Pass in Montana. It is probable that the connection between 

 the Cambrian sea north and south of this island ^ was to the west. 



The area of Cambrian sedimentation in the province outlined be- 

 tween Kootenay Pass and Thompson Pass is approximately 18,000 

 square miles (46,620 sq. km.). In this there is a northwest-southeast 

 belt within which the sediments accumulated to a great thickness and 

 from which they diminished toward the northeast and southwest 

 shore lines of the sea. The greatest known depth of pre-Devonian 

 Paleozoic sedimentation was along what is now the line of the Bow and 

 Kicking Horse Pass and Rivers, where, in the Bow, Goodsir, and 

 Beaverfoot Troughs of the geosyncline, it was over 28,000 feet 

 (8,534.4 m.).° The thinning out to the eastward is shown by the pre- 

 Devonian formations in the Ghost River section on the Rocky Moun- 

 tains front (I on map), which have 1,122 feet (342 m.) of strata that 

 are referred to the Middle Cambrian and 500 feet (152.4 m.) to the 

 Lower Cambrian ; also a deposit of unknown age (Ghost River forma- 



'Geol. Surv. Canada, Report for 1886 (1887), Pt. D, p. 42 D. 

 " Geol. Surv. Canada, Transcontinental Excursion, Guide Book No. 8, Pt. II, 

 1913. Section in pocket. 

 ^ Geol. Surv. Canada, Rep. Cascade Coal Basin and maps, 1907. 

 ■* Problems of American Geology, Yale Univ. Press, 1915, p. 197. 

 ° See footnote p. 200. 



