F. GEOGRAPHY. 251 



ically the region surveyed is comparatively simple. The 

 Book Clifts are the summit of a plateau about 8000 feet above 

 sea-level, continuing unbroken over to the Green River. To- 

 ward the south these cliffs fall off very steeply, forming deep 

 canons that contain tributaries of the Grand River. On the 

 north side, with the dip of the strata, the slope is more gen- 

 tle, although in consequence of erosion numerous precipitous 

 cliffs are found. Descending: in that direction, the character 

 of the country changes. Instead of an unbroken slope, we 

 find that the plateau has been cut in parallel directions by 

 the White River drainage, and the long characteristic mesas 

 of that region testify to the character of erosion. Approach- 

 ing the river, constantly descending with the slight dip of 

 the strata, the bluffs become lower and lower. Thoucrh the 

 creek valleys are wide, and at certain seasons no doubt well 

 watered, the vegetation is that of an arid country. Dwarf 

 pines, pinons, and sage-brush abound, to the almost entire ex- 

 clusion of other trees or grass. Traveling down White River, 

 this character is aoain found to chano-e. A new series of 

 bluffs, occasioned by heavy superincumbent strata, gives rise 

 to the formation of deep canons. 



For 45 miles the party followed the canon of the White, 

 which, no doubt, is analogous to that of the Green, and prob- 

 ably closely resembles that of the Colorado in its detail feat- 

 ures. Vertical walls inclose the narrow river-bottoms, and 

 the slopes of the higher portions are ornamented by thou- 

 sands of curiously eroded rocks. Monuments of all kinds, and 

 figures that can be readily compared to those of animated 

 beings, enliven the scenery, which otherwise would be very 

 monotonous. Two to three thousand feet may be stated as 

 the heioht of the \valls inclosing^ the White River. 



Geologically speaking, the district was one of singular 

 uniformity. Travelino^ westward, the older formations, reach- 



m/ CD 7 7 



ing back as far as the Jurassic, were found. This was fol- 

 lowed by cretaceous, which in turn was covered by tertiary. 

 About three quarters of the region surveyed was found to 

 contain beds belonging to this period. 



Owing to the lithographical character of the strata, water 

 was a rare luxury in this region, and men and animals were 

 frequently dependent upon finding springs. 



Farther west still the Green River group sets in, forming 



