66 FROM FORT LARAMIE TO FORT BRIDGER. 



the eternal sunshine without, that the imagination could desire. 

 It is difficult to account for the river having forced its passage 

 through the rocks at this point, as the hills, a very short distance 

 to the south, are much lower, and, according to present appear- 

 ance, present by no means such serious obstacles as had been here 

 encountered. It is probable, that when the canon was formed, 

 stratified rocks obstructed it in that direction, and that these rocks 

 have since disappeared by slow disintegration. The granite rocks 

 of the pass were traversed in many places by dikes of trap, which 

 were in some instances twenty feet thick, whose direction was 

 east and west. South of the pass, at its eastern extremity, stra- 

 tified rocks, consisting of conglomerate, were observed, in a nearly 

 horizontal position, without exhibiting the least evidence of having 

 been disturbed by the igneous rocks around which they were 

 placed; indeed, they could be traced in close contact with the 

 granite, without any displacement of the strata, proving that their 

 formation must have been subsequent to that of the granite, from 

 the disintegration of which they were composed. The conglome- 

 rate is of the same character as that which was observed before 

 coming upon the carboniferous rocks. The rocks were not ob- 

 served to have any marked dip. It is highly probable that they 

 belong to a period subsequent to that in which the carboniferous 

 rocks were formed, and that the eruption of granite took place after 

 the latter formation, but before that of the conglomerate. No 

 dikes of trap were observed in the granite, except in the immediate 

 vicinity of the Devil's Gate. 



After passing this remarkable canon, we enter upon a broad 

 level valley, bounded on each side by ranges of mountains, their 

 summits broken into curious peaks and eminences entirely 

 destitute of vegetation. Between these winds the Sweetwater, 

 with a current more gentle than . heretofore, its banks covered 

 with grass. An accident occurring to one of the wagons, the 

 remainder of the day was consumed in its repair. Thermometer 

 at sunset, 70°. 



Wednesday/, August 1. — Ther. at sunrise, 33°. Frost during the 

 night ; morning clear, calm, and very beautiful. The road passing 

 occasionally through deep, heavy sand, continued up the right 

 bank of the Sweetwater, which, for the greater part of the morning, 

 flowed at the foot of a long, high range of granite blufis, with here 

 and there a stunted cedar growing from the crevices in the rocks. 

 The valley is here nearly two miles wide, with rolling hills between 



