18 BEPORT UNITED STATES GEOLOGICAL SURVEY. 



upward of six miles, and the maximum height of its walls is nearly 

 3,000 feet. The view from the top of Split Mountain, upon the western 

 verge of the canon, is impressive in the extreme. The rushing river, 

 more than half a mile beneath the observer's feet, appears like a bah 

 bling brook ; and, although securely poised, many minutes elapse before 

 he can command his nerves to sufficient composure for a calm survey of 

 the terrible chasm. Immediately to the north of this point of obser- 

 vation lies the main range of Uinta Mountains, and to the east the 

 broad Yampa Plateau. A broad expanse of lower lands stretches out 

 to the southward and westward, upon the surface of which the struct- 

 ural geology of the region is shown with all the distinctness of a well- 

 drawi; geological map, so slightly are the strata of the formations ob- 

 scured by vegetation, soil, or debris, and so vivid are the various colors 

 of the rocks which compose them. 



WoNSiTZ Valley. — The broad portion of the valley of Green Eiver, 

 which lies adjacent to tliis district, has been called Wonsitz Valley by 

 Professor Powell. Although, when view^ed from the adjacent moun- 

 tains, its surface appears to be only slightly elevated above the river, it 

 is nevertheless true that comparatively little of its surface is within 

 reach of irrigating-waters. The greater part of the surface that is thus 

 irrigable lies upou the west side of the river and beyond the limits of 

 this district; but still many valuable iarms might be e>tablished within 

 its limits and irrigated from Green lliver. 



