58 PROM FORT LARAMIE TO FORT BRIDGER. 



morning has been about parallel with the range of the Black Hills, 

 the base of which could frequently be seen from the more ele- 

 vated portions of the road. The valley of the Platte also was to 

 be seen far in the distance to the north. Crossing La Bontd Creek, 

 encamped near a fine spring, after a fatiguing march of twenty- 

 four miles. 



In passing along the ridge, the only rock exposed consisted of 

 coarse sandstone, with a decided dip to the north-east of 15°, and 

 beds of clay were interposed between the strata. On descending 

 from the ridge into the valley of the fork, some siliceous limestone 

 was found, from which a few fossils were collected. In the same 

 locality were masses of sandstone of a reddish colour. On the 

 side of a ravine to the left of the road, the same sandstone ap- 

 peared to crop out. After crossing this stream, the geological 

 character of the country changed materially. The soil assumed 

 a red colour, being composed principally of red sandstones and 

 shales. To the left rose a high crest or ridge crowned with gray 

 and red sandstone, which was very hard. The general direction 

 of this ridge was N. N. W. and S. S.E., and it was manifestly 

 formed by the upheaving of the strata, the dip being at least 45° 

 to the north-east, while the south-west face of the rocks wais very 

 precipitous. At nearly the highest point of the ridge, a small 

 ravine occurred, containing a layer of coal shale, apparently over- 

 laid by dark shales, and layers of red clay and light slaty shales. 

 The portions of these strata which were exposed were in so decom- 

 posed a state that no fossils could be obtained except very imper- 

 fect ones. 



In the valley of La Bont^ Creek, the soil was found to be formed 

 by the decomposition of highly ferruginous rock. Before the cross- 

 ing of this stream, a ravine exposed a layer of gypsum, which was 

 very fine and white, and of considerable thickness. Overlying it 

 were layers of red sandstone and shales, conformable with the ap- 

 parent dip of the sandstones forming the crest. A mile or two 

 beyond the La Bont^, the gray sandstone was seen cropping out, 

 overlying the red sandstone, and with a considerable dip to the 

 north. Above these were layers of red and light shales and im- 

 pure carboniferous limestone, from which a number of fossils 

 (Avieula monotis, and Cardinia) were collected. The limestone 

 seemed to be composed, to a great extent, of shells : in the more 

 Sandy and slaty shales the fossils were not so numerous. To the 

 left were some eminences composed of the more resisting sand- 



