﻿416 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Apr. 10, 



on the bank of the river ; the oldest, though now close to the water- 

 level, still bearing part of the original prairie-surface, with the same 

 turf that once grew 200 or 300 feet above its present position. The 

 result of this is, that it is seldom that anything can be learnt of the 

 strata which form the full thickness of the river-banks, the more 

 superficial beds being repeated again and again in each slip, so as to 

 give a very exaggerated idea of their development. Above the elbow 

 of the South Saskatchewan the strata are very dark, and contain a 

 large quantity of selenite in radiating crystals. Portions of those 

 soft strata have been formed at this place, by the action of the weather 

 and of the river on their base, into lofty conical mounds, which 

 present a most extraordinary appearance. As no grass has time to 

 grow on them from the constant attrition of their surface, they are 

 perfectly black, and their outline is broken into terraces by the 

 successive lines of ironstone-concretions, which from their hardness 

 retain the soft strata underneath them. At the base of the Cypres 

 Mountains, where these hills begin to rise from the plains that He 

 between them and the South Saskatchewan, the sides of the coulees 

 are formed of the same Septaria-clays, with fragments of Inocerami, 

 and presenting the usual rugged features. This locality would be 

 very favourable for the study of the whole Cretaceous group and 

 the overlying Tertiaries which form the summit of the high lands of 

 the Missouri Cdteau, were it not so dangerous on account of the 

 different hostile Indians that move about in strong parties through 

 it. The Expedition only spent a veiy few days at this interesting 

 place, as it was here that we broke up into parties to explore the 

 Rocky Mountains in 1859. From the few observations I was able 

 to make however, I have been induced to carry the line of these 

 strata from the elbow of the south branch along the cdteau to the 

 Cypres Mountains, besides their outcrop to the north-west, along 

 the line of the Eagle Hills to Fort Pitt. In the prairies .this and 

 the other groups of the Cretaceous System preserve an unaltered con- 

 dition, and rarely present other than a most gentle dip ; but close to 

 the Rocky Mountains, and also within the plications of the older 

 rocks forming that chain, altered shales, highly charged with iron 

 and resting on sandstones, were observed, which at the time I was 

 inclined to consider to be these Septaria-clays, as the concretions had 

 a very great resemblance to those of this group. 



Similar beds with Inocerami were also observed at Nanaimo on 

 Vancouver Island, but I shall describe the whole strata at that 

 place together, and for the present confine myself to the development 

 of the Cretaceous System in the Eastern Prairies. 



Group C — A very large proportion of the higher plains to the 

 west of the Eagle Hill Cdteau is occupied by the fourth great group 

 of the Cretaceous strata. It is met with forming the banks of the 

 lower part of Red Deer River, near where the Expedition crossed it 

 during the last summer's explorations. From that part it rises to 

 the westward, until, at the Hand Hills, the sandstone which forms 

 its upper member has preserved it as outliers, having abrupt escarp- 

 ments to the west. By its marked lithological character it was also 



