205 



mlometres point about 3 kilometres east of Beavermouth 

 station. There the Paleozoic shales and lime- 

 stones abruptly cease and the train runs over the 

 quartzites, slates, and schists of the Beltian 

 Cougar formation. An exceptionally thick and 

 massive quartzitic member of this formation 

 soon appears in bold bluffs on the left ; the same 

 band of rock crosses the river at Beavermouth 

 and continues on a N. 30 W. strike into the 

 mountain to the right of the Columbia. 

 63-2 m. Beavermouth — Alt. 2,430 ft. (741 m.), is 



101-7 km. situated at the confluence of Quartz creek 

 and the Columbia river. The creek represents 

 a case of stream diversion. Its former course 

 lay to the eastward of the high mass of quartzite 

 southeast of the station. Across that rock 

 it had cut a narrow canyon about I ■ 2 kilometres 

 in length and about 75 metres in average depth. 

 Its floor is nearly 300 m. above the Columbia. 

 Specially rapid (Glacial?) erosion on a band 

 of fissile schists paralleling this quartzite on 

 the southwest caused the diversion of the creek 

 to its present course. The high-level canyon 

 is now nearly dry and is open at both ends. 

 Placer mining for gold has been carried on 

 for some years along Quartz creek. 



Two kilometres beyond Beavermouth the 

 railway turns sharply away from the Columbia 

 into the transverse valley of Beaver river, 

 where the Prairie Hills syncline is exposed in a 

 long succession of deep rock-cuts. The syncline 

 is tightly closed. The first outcrops, seen where 

 the railway first meets the Beaver, are 

 cleaved quartzites and slates of the Cougar 

 formation. These are often crumpled in detail 

 but the general dip is about 8o° to the south- 

 west. At the 65-6-mile point the overlying 

 Nakimu limestone, here reduced by shearing-out 

 to a single vertical bed a few metres thick, is 



65-8 m. found. Close by is The Gateway, where the 



105-8 km.vertical Ross quartzites, forming the heart of 

 the syncline, are well exposed. This is the 

 only section where one has a good oppor- 

 tunity of seeing this important formation close 



