white.] SOUTHEEN SLOFE OF THE UINTA MOUNTAINS. 231 



of the lower portion of White River, which is cut through the same 

 formation. 



Continuing my journey I proceeded up the north valley side of the 

 Duchesne to the first creek that comes into it from the northward, and 

 Then up the valley of that creek to the wagon-road. None hut Green 

 River strata were seen on the way until we reached a point two or three 

 miles south of the wagon-road, where strata that appear to he the top 

 of the Wasatch Group were seen. At and in the vicinity of the point 

 where the wagon-road crosses the creek the Uinta Group is seen to rest 

 unconformably upon the Green River Group, the latter having been 

 somewhat tilted and in some places much eroded before the deposition 

 of the latter. 



After leaving the valley of the Duchesne only a few important obser- 

 vations were made concerning the structural geology of the region 

 traversed between there and Salt Lake, and no fossils were obtained 

 from any of the strata over which we. passed. All along the southern 

 flank of the Uinta Mountains drift phenomena were observed, similar to 

 those already noticed as observable along the eastern flank of the Rocky 

 Mountains and in Middle Park ; and also similar to those at the western 

 base of the Rocky Mountains, which are discussed at some length in my 

 report for 1870. The bowlders and pebbles composing the drift found 

 along the southern flank of the Uinta Mountains is composed entirely of 

 the rocks that make up the bulk of those mountains. There being ho 

 granite in that range, of course none is found in the drift along its flanks, 

 wherein it differs materially from that which is distributed along both the 

 eastern and western flanks of the Rocky Mountains, which are largely 

 composed of granite. The drift is found almost everywhere distributed 

 upon the surface, upon the uplands and valleys alike. In some places 

 it is abundant, and in others almost wanting. The terraces are all more 

 or less strewn with it, especially their abrupt sides. The beds of the 

 streams are often so thickly covered with its bowlders as to make cross- 

 ing by our animals both difficult and dangerous. 



Some of the terraces along the flanks of the Uinta Mountains are quite 

 conspicuous objects, their upper surfaces having a very gentle slope away 

 from the foothills. The upper, flat, gently sloping surface is apparently 

 due to erosion and not to acpieous deposition, because the deposit of 

 gravel and bowlders upon it is generally, if not always, thin, while sim- 

 ilar surfaces are produced indiscriminately upon the strata of the Col- 

 orado to the Uinta Groups inclusive. Moreover the surfaces of these 

 terraces have a general correspondence with each other, while the strata 

 out of which they are carved are tdted at various angles. 



Leaving our camp at the wagon-road crossing of the creek before 

 referred to, our way westward was along the line of strike of the Uinta 

 Group, the dip being gently to the southward. ISTot far to the southward 

 a line of hills was seen, j>arallel with our course, which are doubtless 

 mainly composed of strata of the Green River Group ; but I lost sight 

 of that formation after crossing Red Creek. After crossing this creek 

 we came upon strata that are doubtless of Cretaceous age, but these 

 were soon passed, and none but Uinta strata, were seen on our way until 

 Ave reached the head of Strawberry Valley. From this valley our way 

 was again over strata of the Uinta Group to Provo Valley, by way of 

 Daniel's Canon. This canon is a long, deep gorge between high hills, 

 which are, according to King, composed of Uinta strata. They, how- 

 ever, differ considerably in lithological character from any of those of 

 that formation which I have hitherto observed. The rock is of a slightly 



