310 DESCRIPTIVE GEOLOGY. 



were apparently capped by beds of Wyoming Conglomerate ; though, as 

 this idea was based on rather distant observations, the Wyoming Conglom- 

 erate color has not been indicated on the map. 



The moraine ridges also deserve a more careful study than our time 

 permitted. The principal lateral moraines observed were those on the west 

 branch of the Ute Fork, and the east branches of the Lake and Duchesne 

 Forks. In the two latter instances, they stand on the east bank of the 

 present stream ; in the first, on both banks. Smaller detached moraine-ridges 

 were also observed between the streams, coming from shorter local glaciers. 

 There is evidence of considerable erosion since the melting of these glaciers, 

 shown by the depth of the present stream-beds below the base of their 

 ridges, which, in the Lake and Duchesne Forks, is apparently from 500 to 

 1 ,000 feet in the readily-decomposed beds of the Tertiary. On the Ute 

 Fork, it is comparatively small, which is probably due to the fact that the 

 upturned beds, now largely concealed by recent detritus, come nearer to 

 the surface, and have offered more resistance to erosion than the Tertiary 

 gravels. 



