23 



having a thickness of about 650 feet (198 m.) while near 

 Fernie, in British Columbia, they attain a thickness of 

 over 3,000 feet (914-3 rn.). 



The main range of the Rocky mountains, which forms 

 the boundary between Alberta and British Columbia and 

 intervenes between the two groups of coal fields, is 

 composed almost entirely of massive limestone beds which 

 have been determined to be of Devono-Carboniferous age, 

 there apparently having been no break between these twc 

 formations. Towards the top, however, the strata become 

 siliceous containing some thin-bedded quartzites and cal- 

 careous sandstones. The total thickness of these rocks 

 has been estimated by G. M. Dawson to be about 4,000 

 feet (1,219 rn-) [!]• 



The following table shows in descending order the various 

 formations in both groups of coal areas with their respective 

 approximate thicknesses. 



Alberta Areas. 



Name of Formation. 



Age. 



Description. 



Allison Creek ] 



(Belly River ?) \ 

 1,900 ft. + (579111.) J 





Soft, light-coloured sand- 

 stones, with small 

 coal seams near top. 



Benton, 2,750 ft. (838 m.). 



Crowsnest Volcanics, 

 1,150ft. (350-5 m.) 



Dakota, 



2,750 ft. (838 m.) 



•Cretaceous. . . . 



Chiefly dark shales with a 

 few hard, siliceous sand- 

 stone beds. 



Trachytic tuffs and breccias 



Chiefly shaly sandstone 

 with plant impressions, 

 usually green in colour. 



Kootenay 



600 ft. (182 -8 m.) 





Sandstones, shales and coal 

 seams. 



Fernie, 750 ft. (228-6 m.). . 



Limestone Series, 4,000 ft. 

 (1,219 Tl-) 



J u rassic 



Devono- 

 Carboniferous. 



Dark shales with a few thin 

 sandstone beds. 





Massive light-grey lime- 

 stone. 



