456 MINING INDUSTRY. 



against tlie Walisatch witli a strike wliicli shows it to have been affected by 

 the Uintah mass, hes a series of from 8,000 to 9,000 feet of argillo-arenaceous 

 strata, containing large quantities of marine fossils which will be hereafter 

 noticed. This group is bounded on the west by the Wahsatch, and on the north- 

 east and south by the fresh-water Tertiaries which overlie it unconformably. 

 The Weber River itself makes the next important exposure of the rocks. 

 Where it leaves the mountains and turns northward, flowing through Kansas 

 prairie, it cuts through the coal series, exposing about 6,000 feet of similar buff 

 sandstone beds, having a strike nearly due east and west, with a dip of 35° to 

 45° to the north. Continuing down the Weber River a flow of the trachytic lava 

 has buried the series upon the left bank, and the overlying Tertiaries mask it 

 upon the right. But the stream bed itself, wherever the underlying rock is 

 not covered by accumulations of more modern detritus, lays bare the charac- 

 teristic cream-colored sandstone. In this exposure are two or three import- 

 ant beds of coal associated with black, pasty, clay zones of carbonaceous sand 

 material, fine seams of argillaceous mud, and quite a development of marine 

 fossil plants. Continuing still further down the Weber, important masses 

 flank the valley on either side, rising to 800 feet on the west, where they pass 

 under the immense mountain mass of horizontal Tertiary conglomerate. To 

 the east they are laid bare for ten or twelve miles by lateral canons which 

 have been eroded across their upheaved beds, opening an excellent point of 

 observation both of the nature of the materials and their stratigraphical 

 arrangement. At this point (Coalville) and about 2,000 feet below the sum- 

 mit of the series, occur several beds of coal, associated with the same sands 

 and clays, and accompanied by important deposits of marine moUusks. From 

 Coalville to Echo they flank the road on either side, but on nearing the 

 mouth of the Echo Canon they pass under the red Tertiary conglomerates, 

 which stretch northward in an unbroken continuance for many miles. Near the 

 head of the Echo Canon itself the coal series again outcrops, and here is a 

 most interesting instance of the nonconformity of the series, the cream-col- 

 ored coal rocks plainly underlying the red conglomerates, with a difference of 

 dip amounting to 25°. Passing to the east these beds are found to outcrop 

 again in the region of the town of Wahsatch, and at the Bear River, whose 

 west bank is chiefly formed of the upturned coal series, for eighteen miles 



