Geology, &c. of the country west of the Rocky Mountains. 3 
called the Sweetwater. On each side of this river, from a horizon- 
tal plain of sand and sandstone, rise ridges of naked granite rock, 
capped with snow, and to the west could be seen the Wind-river 
mountain towering high, as white as winter could make it. After 
continuing on over a country, first of sandstone then of mica slate, 
with very little timber, we arrived at the head waters of the Sweet- 
water, about one hundred miles from the place where we had fallen 
on to that branch, or four hundred from the Forks of the main Platte. 
Two hours ride over a smooth prairie, and slight swell, now 
brought us on to water flowing into the Pacific Ocean ; not how- 
ever, as our Geographers would lead one to expect, upon the 
waters of the Columbia, but those of the Colorado, of the gulph of 
California. : 
In fact, after leaving the main Platte, there is, as far as it has 
fallen under my observation, no further reliance to be placed upon 
. Maps or accounts of the country. The Arkansaw and Lewis river, 
instead of rising together as has been represented, have not their 
sources within five hundred miles of each other, the waters from an 
extensive region flowing south into the Gulph of California. 
Standing on the dividing ridge between the great Oceans, at an 
elevation, (judging from the temperature of boiling water,) of about 
ten thousand feet, you look down East upon the granite mountains al- 
ready passed, and then to the N. W. upon the snowy Wind-river moun- 
tain, rising probably, five thousand feet above the place where you 
stand. ‘Tothe South on the height of land, stretches an immense 
prairie, as far as the limits of vision, with little variation of surfaces, 
on which are feeding herds of buffaloes; and far to the West, extends 
north and south, a range of mountains of apparently great elevation. 
Our journey now lay, for about one hundred miles, in a N. W. direc- 
tion, along the foot of the Wind-river mountain, across torrents flow- 
ig cold from the same, and at about the same elevation; the travel- 
ling is sometimes almost obstructed by the granite bowlders, which 
showed conclusively the character of that mountain. On this mountain 
are said to rise the Wind-river and other branches of the Yellow 
Stone, the Missouri, Lewis river and Colorado. It was now the first 
of July, and we occasionally met with drifts of snow, and frequently 
had frost at night, although at noon the thermometer ranged from 60° 
to 70° ; the nights were always clear, and the days were, generally, 
so too, although sometimes attended by slight squalls of rain, snow 
or hail. In one of the snow squalls, on the 4th of July, we reached 
