330 GEOLOGY OF THE DENVER BASIN. 



a third of a mile wide and is bordered by bluffs 50 feet high. The 

 confluence of Turkey and Bear creeks is in the middle of the bottom 

 lands northwest of Mount Carbon, upon Laramie beds. Mount Carbon is 

 a remnant of the early terraced bench lands now separated by the valley 

 of Turkey Creek and adjacent lowlands from the main body of uplands 

 nearer the foothills. Its altitude above the creek is between 300 and 350 

 feet. The shape is elliptical, the longer axis east and west. South of Mount 

 Carbon the conglomerates at the base of the Arapahoe form a lino of 

 prominent combs from which the distance to the coal measures, about 900 

 feet, may be closely laid off — the basal sandstones of the Laramie forming 

 no outcrop along here. North of Bear Creek the prairie is cut by a 

 number of shallow coulees, one of which enters the creek valley along the 

 base of the Laramie, the coal having been opened both in this coulee and 

 upon the prairie to the east. 



In the northern fare of Mount Carbon is an excellent exposure, in 

 section, of the great fold along the front of the Colorado Range. The 

 vertical portion of the beds appears in the coal-measure sandstones and the 

 heavy sandstones and conglomerates at the base of the Arapahoe, and 

 occupies the western half of the hill: the eastern half of the hill exposes 

 the remainder of the Arapahoe and the basal members of the Denver 

 formation, the latter forming a conspicuous knoll of gently dipping strata 

 a little northeast of the main elevation. The fold itself shows in section 

 in the eastern third of the hill, and is traceable by occasional visible 

 outcrops of the more resisting beds and by a searching examination in the 

 slightly covered strata by means of the pick. This structure continues 

 both north and south of Mount Carbon, but the actual flexure is no longer 

 visible owing to the planing down of the prairies and the comparatively 

 insignificant height of the bluffs bordering the streams. 



Both the prairies to the north of Bear Creek and the cap of Mount 

 Carbon consist of a light, but uniformly distributed Quaternary gravel, 

 of rather coarse material, through which the harder beds of the vertical 

 portions of the underlying formations occasionally outcrop. 



The strike of the beds in the Mount Carbon region is a gently varying 

 curve from N. 20° W. 2 miles south of Bear Creek to N. 60° W. immedi- 

 ately north of the creek, the region lying just within the southern confines 



