TO JUNCTION OF GRAND AND GREEN RIVERS. 93 



of the sandstone buttes, which I have described, and it has often happened to me, after 

 a fatiguing climb to the top of some high cliff or pinnacle, to find its smooth-washed 

 summit-rock scooped out in cavities from- 2 to 20 feet in diameter, holding sometimes 

 many barrels of the clearest rain-water, and affording me the two rarest possible 

 luxuries in this arid region a drink of pure water and a cleansing and refreshing bath. 

 The Ojo Verde is a copious spring in a canon cut out of the red sandstone, ten 

 miles west of La Teneja. The surrounding country is very sterile, sparsely set with 

 sage bushes and small cedars, but about the spring the bottom of the canon is cov- 

 ered with the greenest and most luxuriant grass. The La Sal Mountain shows very 

 finely from this point, distant twenty miles. It is seen to be composed of several short 

 ranges, separated by narrow valleys, having a trend several degrees north of east, but 

 these are set somewhat en echelon, and the direction of the longest diameter of the mount- 

 ain mass is north-northwest and south-southeast ; such, at least, seems to be the 

 structure of this sierra as seen from a distance. Perhaps closer inspection would show 

 that the view obtained from this point was in some respects deceptive. Of the compo- 

 sition of the Sierra La Sal we know nothing except what was taught by the drifted 

 materials brought down in the canons through which the drainage from it flows. Of 

 this transported material we saw but little, but that consisted mainly of trachytes and 

 porphyry, indicating that it is composed of erupted rocks similar to those which form 

 the Sierra Abajo, of which it is in fact almost an exact counterpart. From the cliffs 

 over Ojo Verde we could see the strata composing both the upper and second plateaus, 

 rising from the east, south, and southwest on to the base of the Sierra La Sal, each 

 conspicuous stratum being distinctly traceable in the walls of the canons and valleys 

 which head in the sierra. It is evident, therefore, that the rocks composing the Colo- 

 rado .Plateau are there locally upheaved, precisely as around the Sierra Abajo and the 

 other isolated mountains which I have already before enumerated, and to which I shall 

 have occasion again to refer. 



VALLEY OF THE COLORADO. 



The general features of the trough of the Colorado, at the junction of Grand 

 and Green Rivers, have been already sketched, but the detailed description of our ex- 

 plorations of this remarkable region yet remains to be given. From the difficulties in 

 the way of such exploration, reported by our scouts, it was not thought advisable to 

 attempt to reach the river with our entire party. A depot camp was therefore estab- 

 lished at Ojo Verde, where most of the men and animals remained, while a small de- 

 tachment, with which I was connected, made the desired reconnoissance of this part of 

 our route. Of this excitrsion I find in my journal the following descriptive notes: 



Any list 22. Started this morning for the junction of Grand and Green Rivers, 

 Captain Macomb, Lieutenant Cogswell, Mr. Dimmock, Mr. Campean, myself, and 

 three servants forming the party. On leaving camp we struck southwest, gradually 

 ascending for six miles, when we reached the brink of a magnificent canon twelve 

 hundred feet in depth, called, from the prevailing color of its walls, Canon Colorado, 

 into which with great difficulty we descended. The summits of the cliffs are here 

 nearly five hundred feet above the Ojo Verde, composed of the same rock exposed 



