HYPOGEIC WOliK, 



359 



3. The Laramide Mountain System, including the Wasatch Range. 



The Laramide system of mountain ranges extends along the summit of the 

 Rocky Mountains far northward into British America, and southward into 

 Mexico. In Britisli America, just nortli of Montana, the upturned belt lies east 

 of the Archaean protaxis. In the United States it occupies the summit region 

 of the mountains, between the line of the Wasatch Archaean and the Front 

 Eange or protaxis. Dr. G. M. Dawson states that, in British America, the 

 belt of upturned rocks along the summit of the Rocky Mountains extends 

 from Montana northwestward, with a small interruption, to the Arctic Ocean, 

 which it reaches west of the Mackenzie delta. 



The rocks involved were those of all Paleozoic and Mesozoic time, Cam- 

 brian beds making the bottom, and the Laramie, or the uppermost forma- 

 tion of the Cretaceous, the top. The whole thickness of the series in 

 British America, between 50° and 54° N., is 34,000 feet (R. G. V. McConnell, 

 1887), and in the region of the Wasatch, about 31,000 feet (C. King, 1878) ; 

 as nearly as has been learned this was the final depth of the geosyncline in 

 which the deposits were accumulated. 



The facts from British America, as reported by McConnell (1887) and 

 Dawson ( 1886), are much like those of the Appalachian region. 



The following figures, by McConnell, from a point in the range not far 

 from the line of the Canadian Pacific Railway, show the Cretaceous rocks 



332 



333 



334 



D Cr 



(Cr, Cr) overlaid by the Cambrian (C), or the bottom beds of the Paleozoic, 

 almost horizontally for a width of two miles ; and the describer states that 

 the whole width of the overthrust of the Cambrian at this place is, by his 

 estimate, seven miles. These Cambrian beds are overlaid on the west by 

 Devonian beds (D), and by the Carboniferous (Cb', Cb'), which have a fault 

 (F) between them. The thrust is away from the ocean, as in the Appa- 



