﻿424 



PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



[Apr. 10, 



- '(. 



As developed at the Mountain House, this formation, whatever 

 its exact age, may be described as con- 

 sisting of sand and clay in varying pro- m |jwf y. 



portions — great ridges of pure sand- 



stone, including basins in which havo § rfi'llit ■' j 1 1 jj ■ 



been deposited clays and clay-sand- r< 

 stones charged with coal and ironstone Q 

 in large quantities. s. 



On the Athabasca River, the valley "| 

 from Fort Assineboine in latitude 

 54° 50' up to the outer range of the •§ 

 mountains at Deadman's Rapid, cuts ^ 

 through argillaceous sandstones, with ;§ 

 beds of clay and coal of the same land 

 as those at the Mountain House. The 

 sandstones are in much greater propor- 

 tion however, and the lignite-beds are 

 more rarely seen, than in the sections 

 along the North Saskatchewan. At 

 Deadman's Rapid these strata are suc- 

 ceeded by grits and clay-shales in 

 regular beds, undisturbed at first, but, 

 on approaching the mountains, found 

 to be implicated in the late upheavals. 



On Red Deer River the lignite- 

 formation was observed at various 

 points, tho lowest being at the Hand 

 Hills, which have already been alluded 

 to in speaking of the " banded clays." 

 By again referring to fig. 5 (p. 418), it 

 will bo seen that a Hat plain extends ^ g 

 back from the summit of the river- 

 valley towards the base of the hills 

 where the white mud-swamps are situ- 

 ated, but which is cut up by great 

 ravines, which gradually deepen as 

 they approach the river. The river- 

 valley itself is half a mile wide, and 

 270 feet deep. 



At the commencement of one of the 

 ravines, about three miles back from 

 the river, wero found the fossils before 

 mentioned (Ostrea cortex); and in ^ i^'lKf 

 another, at only a quarter of a mile ^ j , \ \ . 



back from the river-valle}', that fossil S *lll[|!ijii'i^Hlil!l 

 was again found in the highest part of ~" s 

 the bank, along with Cytherea Texana, -»*»J09i 

 showing that these beds must form the surface of the level flat. At 

 the mouth of the same ravine (Shell Creek), the following sections 

 were observed in the bank of the valley of Red Deer River, the beds 

 being to all appearance horizontal : — 



6Q 



