22 



12,000 feet, and runs east throughout its whole length; at 

 first, a little north of east and then with a single bend going 

 southeast. It seems to reach its maximum in Gilbert's Peak, 

 which cannot be far from 14,000 feet of elevation. From this 

 point it descends till it terminates near the Green River. 

 The range forms an immense ridge, with an almost level, but 

 badly broken up belt on top, which has an elevation of about 

 6000 feet above the table-land on the north, and apparently 

 about 7000 feet above the similar table-land on the south. 

 The valleys are numerous, deep, and narrow, except at the 

 head, and extend quite to the summit. Between these val- 

 leys on the north are the transverse and generally unbroken 

 ridges by means of which the summit can be reached by a 

 gradual ascent. On the south these transverse ridges seem 

 to be very much broken toward the summit. The opposite 

 valleys start from nearly the same point, and have between 

 them only a thin precipitous wall, which erosion is slowly re- 

 moving. Gilbert's Pass at the head of Smith's Fork is such 

 a point, where the wall has been sufficiently worn away to 

 admit of the construction of a road across it. There are few 

 if any other such places at present.* 



The sides of the ridges which bound these valleys are 

 generally masses of boulders and debris in sitti, making their 

 ascent almost an impossibility, and travelling a very difficult 

 operation. The country to the north from the end of these 

 ridges descends in a series of terraced plateaus of soft earth, 

 the slopes of the terraces being generally as steep as the 

 earth will stand. 



The whole top of this elevated belt of country is very badly 

 broken up by cracks in many places, affording a fine chance 

 for the study of dynamical geology. It seems to have been 

 the favorite battle-ground of the elements, some of the peaks 

 having- been literally crushed into a mass of huge boulders. 



Our topographic survey in this valley has been carefully 

 worked out and embodied in the principal map which accom- 

 panies this report. The diary of the trip will give the daily 

 occurrences, and for this reason it will only be necessary 

 here to indicate the route taken and the bases which were 



* See Geol. Survey of 4Oth Parallel vol. ii. p. 257. 



