34 



KUometres wcst along the foad and railway. Overlying 

 the Dakota rocks the Crowsnest volcanics can 

 be well seen in a number of cuts along the rail- 

 way to the west of Coleman; they here reach 

 a thickness of 1,150 feet (350-5 m.). Specimens 

 from this locality have been microscopically 

 and chemically examined by C. W. Knight 

 who distinguished four predominant rock types, 

 viz. : augite-trachyte breccia, tinguaite, ande- 

 site tufif, and analcite-trachyte tuff [4]. 



From Coleman to the east end of Crowsnest 

 lake, the railway crosses the Cretaceous rocks 

 in regular ascending order, the dip of the strata 

 gradually flattening to nearly horizontal. West 

 of Coleman the valley widens, is more open, 

 and shows well-marked terraces, and good 

 views can be obtained of the Rocky mountains 

 and of Crowsnest mountain. This last named 

 peak, by reason of its isolated position, forms 

 a notable landmark for many miles; it reaches 

 an elevation of 9,125 feet (2,780 m.) or about 

 4,800 feet (1,219 1TI-) above the valley. The 

 upper part of the mountain is composed of 

 almost horizontal beds of Palaeozoic limestone, 

 which have overridden Cretaceous sandstones 

 of the Allison Creek formation along a great 

 thrust plane. The Palaeozoic rocks to the 

 east of Crowsnest mountain have been removed 

 by denudation, the valley of Allison creek 

 forming a low depression, underlain by Creta- 

 ceous rocks, between Crowsnest mountain and 

 the main range of the Rocky mountains. 

 204-3 rn. Sentinel — A short distance beyond the 

 328-8 km. east end of Crowsnest lake the contact of the 

 Cretaceous and Palaeozoic rocks is crossed, 

 the Cretaceous beds dipping under the Devono- 

 Carboniferous limestone along the overthrust 

 fault-plane already mentioned. Half way up 

 the lake, on the north side, a remarkable spring 

 issues from a large overhung grotto in the face 

 of a limestone cliff, and constitutes the chief 

 feeder of the lake. 



All along the north shore of the lake as 

 far as the summit, the Palaeozoic rocks are well 



