160 Expedition to the 



neighbourhood. We had recendy seen great numbers of 

 elk, and killed one or two, which we had found in bad con- 

 dition. 



6th. Numerous ridges of rocky hills traverse the country 

 from northeast to southwest, crossing the direction of the 

 river obliquely. They are of a sandstone which bears suffi- 

 cient evidence of belonging to a coal formation. At the spot 

 where we halted to dine, one of these ranges, crossing the 

 river, produces an inconsiderable fall. As the whole width of 

 the channel is paved with a compact horizontal sandstone, 

 we believed all the water of the river must be forced up to 

 view, and were surprised to find the quantity something less 

 than it had been almost six hundred miles above in the same 

 stream. It would appear, that all the water, which falls in 

 rains, or flows from springs in an extent of country far greater 

 than Pennsylvania, is not sufficient to supply the evaporation 

 of so extensive a surface of naked and heated sands. 



If the river, of which we speak, should, at any season of 

 the year, contain water enough for the purposes of naviga- 

 tion, it is probable the fall, occasioned by the rocky traverse 

 above mentioned, will be sufficient to prevent the passage 

 upwards. The point is a remarkable one as being the locality 

 of a rare and beautiful variety of sandstone. The rock which 

 appears in the bed of the river is a compact slaty sandstone 

 of a deep green colour resembling some varieties of chloritic 

 slate. Whether the colour depends upon epidote chlorite^ or 

 some other substance, we were not able to determine. The 

 sandstone is micaceous, but the particles of mica, as well as 

 those of the other integrant minerals, are very minutely di- 

 vided. The same rock, as we found by tracing it to some 

 distance, becomes of a light gray colour, and contains exten- 

 sive beds of bituminous clay slate. Its stratifications are so 

 little inclined that their dip cannot be estimated by the eye. 

 This point, though scarce deserving the name of a cataract, 

 is so marked by the occurrence of a peculiar bed of rocks 



