﻿1861.] 



HECTOK — ROCKY MOUNTAINS, ETC. 



413 



two groups of strata produces the rugged appearance of this range, 

 the mountains being in general formed by masses of synclinal folds, 

 while the valleys mark anticlinal fractures. The valley between the 

 first and second range marks a great trough in the strata in which 

 patches are preserved of chocolate- coloured ferruginous shales with 

 beds of grit and layers of ironstone, and which are the same seen in 

 the above sections resting on the flanks of the limestone mountains, 

 belonging to a more recent formation, and to which I have previously 

 alluded (p. 427). In the second range we have the same limestones 

 and shales repeated as in the first ; but at the base I observed traces 

 of a magnesian limestone of a buff colour, containing Atrypa reticu- 

 laris, a true Devonian fossil (c, fig. 11). Towards the west this range 

 everywhere in the mountains presents a sheer wall of vertical lime- 

 stone, the ragged edge of the beds forming the Saw-back Range. 

 The change in the look of the mountains that now takes place may 

 be well seen, as on Bow River in fig. 13, where the east side of this 



Fig. 13. — Sketch of the Second Great Valley, on Bow River, 

 in the Roclcy Mountains. 



valley consists of vertical strata, while on the west side the moun- 

 tains are formed of cubical masses of strata that are almost horizontal. 

 These are of hard quartzite-sandstone, passing into conglomerate, 

 and capped by hard limestone, with the ferruginous shales resting 

 obliquely on their sides at the line of fracture. At the source of the 

 Pipe-stone Creek the mountains form part of the second range, 

 and there I procured some fossils that have been distinguished by 

 Mr. Salter as Orthis, Lingula, Euomphalus, and from the limestone 

 Lithostrotion, which are either Carboniferous or Devonian. On 

 the Athabasca River gneissoid rocks, traversed with quartz-veins, 

 were observed to form the floor of the second longitudinal valley, and 

 in descending the valley of Vermilion River, and also that of Blae- 

 berry River, talcose shales were met with also, forming the floor of 

 the valley (e, figs. 11 & 14). On Kicking-horse River in the third 

 range, we have the mountains again formed of blue limestone, to- 

 gether with a compact blue schist with red bands, giving a curious 

 striped aspect to the rock. This schist or slate-rock forms the 

 highest points of the mountains in the above district (d, fig. 14). 



The third longitudinal valley is that in which the Columbia 

 and Kootanie Rivers flow in opposite directions parallel with the 

 range. Along the eastern shore of the Columbia Lakes we find the 

 mountains again composed of the Carboniferous limestones which form 

 the eastern ranges, but resting unconformably on slates (e, fig. 14). 



