EASTERN FOOT-HILLS. 53 



tiles, abundant in the Upper Creaceous sandstone, through the Smoky Hill 

 country, in Kansas. 



But a short distance north of the railroad occurs an outlying ridge of 

 Carboniferous limestone and the lower red sandstones, with a strike a few 

 degrees west of north and a dip 30° to the eastward. Here the lower red- 

 dish-gray sandstones, with the red arenaceous limestone, are well developed, 

 overlaid by massive blue limestone, passing up into light-gray arenaceous 

 limestone. . 



Along the immediate line of the railroad, the Pliocene formation extends 

 up to the Archaean body, but directly south the same red sandstones and 

 blue limestone, which occur to the north, come again to the surface, with 

 a dip of only 20°. The limestone has been quite extensively quarried for 

 burning in kilns, and is said to furnish a very good quality of lime, which 

 formerly supplied Cheyenne, Greeley, and the neighboring towns. 



Coal-Measure fossils were found here ; among them were identified — 



Produdus cora. 

 Athyris subtilita. 



Still farther southward, the Palaeozoic rocks occur inclined against the 

 Archaean gneisses at an angle of 8° to 10°. They appear to form an unbroken 

 line nearly down to the old Denver and Laramie stage -road, presenting an 

 abrupt wall to the main moimtain mass, but falling off with gentle slopes 

 toward the plain. The outlines of overlying formations are somewhat poorly 

 defined, owing to the very irregular erosion of the Pliocene and accumula- 

 tions of Quaternary deposits. South of the Wyoming and Colorado bound- 

 ary-line, all the formations, including the Fox Hill beds, are well exposed, 

 dipping at various angles; the Dakota Cretaceous capping the higher and 

 more prominent ridges, and the Colorado Cretaceous, with the upper sand- 

 stones, stretching far out upon the plain. 



The uplifts of Carboniferous limestone would appear to terminate near 

 where Box Elder Creek turns and breaks through the sedimentary ridges, 

 and from there southward the Triassic Red Beds occur lying next the 

 Archaean. 



