CONDITIONS OF MINING. 329 



who opened a 7-foot seam of coal, but abandoned it after a year's work- 

 ing. Coal taken out of the old prospect entry near by, that has been ex- 

 posed for three years, is hard and firm. 



Taggart's claim, 4,500 feet in altitude by aneroid, shows a dip of 1° to 2° 

 toward the south. A short entry shows the following section, which was 

 taken at the outcrop and does not, therefore, fairly represent the seam : 



Solid sandrock 



Decomposed brown clay 36" 



Coal 24" 



Lignite bone 42" 



Coal, forming entry roof 12" 



Bony, dirty coal 12" 



Clean coal 4" 



Slaty dirt parting 2o" 



Coal, clean 23" 



Carbonacious slate parting 5" 



Coal 24" 



This part of the field can be mined cheaply, owing to the flatness of 

 the seams ; but the narrow gulches give no dumping ground. The lack 

 of transportation is the only great obstacle to the rapid development of 

 the mine. 



Near Clarkes fork the ridge shows a heavy outcrop of sandstone com- 

 posed of granitic grains and forming ridges 150 to 175 feet high, the beds 

 dipping southward 4°, and coal seams lying beneath the sandstones. 

 East of Clarkes fork the soft clays of the Tertiary (?) appear, the river 

 cutting through a low synclinal arch. 



The continuity of the coal field toward the southeast is interrupted by 

 the river valley and the eroded basin of Grove creek, now a broad wash- 

 plain. At the head of this gravel plain the Cretaceous sandstones and 

 clays, carrying lignites, dip 5° toward the mountains, the summit being 

 about 5,320 feet in altitude, and the ledges abutting against a Carbonif- 

 erous conglomerate dipping northward 75° and underlain by massive 

 limestone cut into picturesque, castellated forms by the mountain tor- 

 rents. The fault line extends southeastward, so far as can be seen, at least 

 a couple of miles beyond here. From this point to the most westerly 

 spot visited, some eight miles in all, the structure is the same. East of 

 Clarkes fork, Pryer mountain shows beds dipping southward. 



Age of the Rocky Four* Coat,. 

 Below seam number i there is some 60 feet of sandstone weathered 



down to a slope, with a bold outcrop of massive sandstone some .",(> to 40 

 feet in thickness below it, This rock is coarse, formed of granite debris, 



