72 GEOLOGICAL SURVEY OF THE TERRITOEIES. 



and tlie monoclinal cliaracter of the canon becomes more apparent. 

 Fragments of the quartzites may be seen on the west side, high up on 

 the granites inclining northeast ; while on the right or east side they 

 incline in the same direction and dip beneath a vast thickness of varie- 

 gated sandstone and shales. At first the high mountain-ridges, 1,200 

 to 2,000 feet above the bed of Eagle Eiver, are granite or simply capped 

 with patches of the quartzite. As we descend the Eagle Eiver an 

 increasing thickness of the sedimentary beds is observed on that 

 side, forming a steep slope, while on the right or east side the abrupt 

 edges of the variegated sandstone and shale rise at least 2,000 feet, 

 forming the high rounded ridge between the Holy Cross and Blue 

 Eiver groups. Opposite the junction of Eoches Moutonnes Creek with 

 Eagle Eiver there is a very high, nearly vertical, bluff, showing a re- 

 markable section of the variegated beds, which are i>robably of Carbon- 

 iferous age. 



We have already noticed the quartzites resting on the granites, and 

 above the quartzites are impure arenaceous limestones. As we descend 

 Eagle Eiver, these rocks, which have a more ancient aspect, and which 

 I regard as of Lower Silurian age, pass beneath the bed of the river, at 

 the entrance of Eoches Moutonnes Creek, and we have on the east or 

 right side of the river the series of strata whi-eh may be described briefly 

 as follows, in ascending order : 



1st. A group of rather light-red sandstone, varying in -shades of 

 color, oftentimes in massive layers varying from a few inches to 30 feet 

 thick, with partings of arenaceous shale, varying from a few inches to 

 6 feet in thickness. The two upper layers of sandstone are fine-grained, 

 and break into quite regular vertical columns. The lower bed is about 

 12 feet thick. The layers or strata are all irregular in thickness in the 

 horisontal extension, sometimes thinning out to a few inches, and then 

 increasing to several feet. In texture the rock presents every shade 

 from a flue-grained sandstone to a coarse conglomerate, and these 

 changes may occur in the same stratum within a few feet. There are 

 twenty-two layers of sandstone in this group, varying from 2 to 30 feet 

 in thickness, and the aggregate thickness is about 500 feet. Some shade 

 of red is the prevailing color. 



2d. Then comes a series of similar beds, evidently portions of the 

 same group, but in this locality marked by difference in color, being 

 mostly yellowish- gray or brown, sometimes with a reddish tinge. The 

 first bed is about 6 feet thick with the same vertical columnar fracture, 

 which at a distance gives to the rock the appearance of basalt. This 

 group comprises twenty-four beds of sandstone, varying from 2 to 

 40 feet in thickness, with shaly partings varying from a few inches 

 to 4 feet. This upper group is much finer in texture than the lower 

 group, yet all the layers indicate the deposition of the sediments in 

 shallow as well as moving waters, by the oblique laminfe and the irreg- 

 ular thickness from point to point. The shaly partings are in many 

 cases very micaceous, and might be termed micaceous shales; while the 

 coarser sandstones, or pudding-stones, are made up of pebbles of quartz 

 mostly, and so far I could detect no fragments of the sedimentary rocks. 

 The shales are also variable in color from yellowish-brown to a light gray, 

 then changed into what may be called mud-sandstone, in groups vary- 

 ing from 50 to 200 feet in thickness. . Sometimes the mud-shales are 

 separated by a few feet of coarse sandstone or quartzite. The difference 

 in the texture of these layers may be detected at a distance by the 

 style of weathering; the sandstones fracture with a square vertical 



