314 DESCRIPTIVE GEOLOGY. 



the East Fork of the Duchesne, represented on Map II, are seen the topo- 

 graphical effects of the change in strike from 10° north of west to 25° south 

 of west; the re-entering angle in the strata being produced by longitudinal 

 compression of the Uinta fold. The upper part of Red Fork also runs parallel 

 with the strike of the upturned beds, and has been cut in the line of a deposit 

 of coal enclosed in a white fine-grained friable sandstone, which is considered 

 to correspond to the coal seam found in the Colorado Cretaceous on Ashley- 

 Fork, though no fossils were obtained from any of the upper beds at this 

 locality. The outcrops of coal were too much weathered and decomposed 

 to afford any indications* as to its economical value, consisting mostly of 

 brown earthy carbonaceous material. Below the upper bend of Red Fork, 

 a sulphur spring issues from the sandstones overlying the coal. 



To the eastward, the beds of the Triassic, Jurassic, and Cretaceous pass 

 under the almost horizontal Tertiaries of the Uinta Eocene, which cover the 

 whole region along the headwaters of the Uinta. These Tertiaries are exposed 

 in great thickness, and consist mostly of coarse buff and chocolate-colored 

 sandstones and loose gravelly conglomerates, attaining a thickness of several 

 thousand feet. They have been deeply cut tln'ough by the streams which flow 

 into the Uinta River, and in some places, notably at the junction of Kern Creek 

 and where the Uinta River cuts through the southern end of Kern Ridge, 

 beyond the limits of the map, isolated outcrops of unconformable upturned 

 beds, limestones and sandstones, are found exposed, but too limited in 

 extent to afford definite indications of their age. It would appear probable, 

 however, that similar secondary flexures in the Mesozoic strata exist in this 

 southern angle of the Wahsatch and Uinta Ranges as are found in the 

 northern angle. The plateau-like summits of the highest of the Tertiary 

 ridges are found to be covered by beds of coarse conglomerate, resembling 

 in character those of the Wyoming Conglomerate observed on the north 

 slopes of the range, to which formation they have therefore been assigned. 

 The Tertiaries occupy the ridges which border Strawberry Valley, and 

 those which separate the waters of this valley, which flow into the Uinta, 

 from those of Hobble's Caiion flowing into Utah Lake. They doubtless 

 extended at one time to the very flanks of the Wahsatch; but the region 

 west of Strawberry Valley, in the upper portions of Hobble's Canon, and 



