76 DESCRIPTIVE GEOLOGY. 



and angular pebbles, in places passing into a bard conglomerate ; but none 

 of the beds observed exhibit the tendency to form quartzite, as on the oppo- 

 site side of the range. The lower sandstones pass up into granular arena- 

 ceous limestone, with a reddish-yellow color, intercalated with layers of 

 lighter shade, and in turn overlaid by heavy massive blue limestone, reach- 

 ing to the top of the series. Probably, the nan-ow layers of sand-rock and 

 conglomerate, which may be detected in the blue limestone along the east 

 base of the range, occur here, but the opportunities offered for observing 

 such details are by no means as good. In thickness, the Palaeozoic beds 

 west of the hills develop not far from 1,200 feet of sandstone and limestone 

 strata. 



All palaeontological evidence obtained from these beds would tend to 

 show that they belonged to the Coal-Measure limestones. No fossils were 

 found in the upper members of the series, as on the east side ; but, ou the 

 other hand, in several localities, within 200 or 300 feet of the base, charac- 

 teristic Coal-Measure forms are abundant. 



Near where the road which crosses the range, following up Sybille 

 Creek from the east, passes over the Carboniferous limestone upon the 

 west side, the beds which are found dipping from 5° to 7° consist of a 

 hard, moderately fine-grained, bluish-gray limestone, carrying through a 

 vertical range of 200 or 300 feet, and reaching at least within 200 feet 

 of tlie base, the following Carboniferous species: 



Producius Prattenianns. 

 Produdus costatiis. 

 Athyris svMilita. 



Near the top of the Cheyenne Pass, in a very similar-looking limestone, 

 and doubtless the same horizon, were found — 



Productus semireticulatiis. 

 Produdus cora. 

 Athyris subtilita. 



BeUerophon f 



OrtJioceras f 



Still farther southward, some 5 miles northwest of Shemian, the lower 



