WIUTE.1 SOUTHERN SLOPE OF THE UINTA MOUNTAINS. 231 



of tlio lower i)ortion of White Eiver, wliicli is cut tlirougli the samo 

 Ibrinatioii. 



Coiitiiiuing my journey I i)rocee(led up the uorth valley side of the 

 J.)uclK'sne to the lirst creek that comes into it from the northward, and 

 then up llie valley of that creek to the wagon-road. None but Green 

 liiver strata were seen on the way until we reached a poiut two or three 

 miles south of the wagon-road, where strata that ajtpear to be the top 

 of t\ni Wasatch Group v»'ere seen. At and in the vicinity of the point 

 where the wagon-road crosses the creek the Uinta Gn)up is seen to rest 

 nnconforinably upon the Green liiver Group, the latter having been 

 somewhat tilted and in some places much eroded before the deposition 

 «>f 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 

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

 those already noticed as observable along the eastern Hank of the llocky 

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

 base of the IJocky Mountains, Avliich are discussed at some length in my 

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

 along the southern Hank of the Uinta Mountains is com]>osed entii'ely of 

 tlie rocks that make u]) the bulk of those mountains. There being no 

 grainte in that range, of com\se none is found in the drift along its flanks, 

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

 ejistein and western flanks of the Kocky Mountains, which are largely 

 composed of granite. The drift is Ibund almost everywhere distributed 

 upon the surface, ujion the uplands and valleys alike. In some idaces 

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

 or less strewn with it, especially their abi'U]it sides. The beds of the 

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

 ing by our animals both ditiicult and dangerous. 



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

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

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

 due to erosion and not to aqueous 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 tilted 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 beuig gently to the southward. Not far to the southward 

 a line of hills was seen, parallel with our course, which are doubtless 

 mainly composed of strata of the .Green Iviver Group ; but 1 lost sight 

 of that fonnation after crossing lied 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 

 we reached tlic head of Strawberry Valley. From tliis valley our way 

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

 Daniel's Cafion. This canon is a long, deei) gorge between high hills, 

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

 ever, dili'er considerably in litliological character from any of those of 

 that formation which I have hitherto obsei-ved. The rock is of a slightly 



