68 ROUTE NEAR THE FORTY-FIRST AND FORTY-SECOND PARALLELS. 
beneath its surface. As we go west it loses this character, and about the 99th and 100th 
meridians becomes, for the most part, dry and almost barren. The islands of the Platte are 
well wooded as far west as the 99th meridian. From the 100th meridian to the base of the 
Black Hills, it is in summer hot and arid, and the summer winds, in many places, as they come 
from the hills, seem to have just left a furnace. Wood and grass in this portion (250 miles) 
are very scarce. 
The favorite feature of the great section east of the mountains is the almost direct flow of the 
Platte and its branches from west to east, enabling us to obtain a location along the foot of the 
bluffs, which will give for the most a continuously ascending grade, and avoid the rolling coun- 
try. Wood, water, and grass will also be found here more abundant than on the divides 
between the streams. This location, however, will no doubt involve much cutting and em- 
bankment, with frequent culverts. 
There are two routes proposed for crossing the great plateau west of the Black Hills: one 
by the South Pass, in latitude 42° 20’, longitude 113°; and the other by Bridger’s Pass, in 
latitude 41° 13’, longitude 110° 48’. If we begin at Council Bluffs, a route through either 
pass would have a common location in the valley of the Platte, to the junction of the North 
and South forks. Here they would separate; the one by the South Pass taking the North fork 
and Sweet Water, and the one by Bridger’s Pass taking the South fork and Lodge Pole creek. 
The elevation at Council Bluffs is 1,300 feet; at the junction of the forks of the Platte, 2,900 
feet; distance, 300 miles; average grade, 2 feet per mile. 
As regards a connexion with Great Salt Lake City, the latter would be the more direct; but 
it is still a question as to which would be the better route for a railroad, though Captain Stans- 
bury, who was over both, is positive in his preference for Bridger’s Pass. Unfortunately he 
had no barometer or means of measuring elevations, and much is left to be inferred. The fol- 
lowing facts concerning the two routes are extracted from Fremont’s and Stansbury’s reports : 
By the South Pass.—The Platte river, 30 miles above Fort Laramie, and 220 miles above 
the junction of the forks, comes through a gorge with vertical walls, 200 to 400 feet high, — 
formed by spurs from the Black Hills, and changes its character from a mountain stream to 
a river of the plains. Thence to the Red Buttes, 117 miles, there are numerous streams 
coming into the Platte from the Black Hills, which have made deep cuts in the earth near 
their mouths. The railroad would probably, through this portion, keep near the present 
wagon-road some miles to the south of the Platte, where the greatest obstruction Fremont 
found to his wagons was the strong growth of artemisia. A road along this section would be 
expensive, though the grades would probably not be difficult. At the gorge of the Red Buttes 
‘the river is not much pent up, there being a bank of considerable though variable breadth 
on either side.’? A road could be located through this. Thence to the Hot Spring Gate, 34 
miles, is an open valley. Above this point, the Platte is ‘exceedingly rugged and walled in 
by cafions.’? The road just below the Hot Spring Gate should turn off to the north, up the 
sandy bed of a dry creek to the summit of the Hills, the peaks of which are only 800 feet 
above the Platte; grade, 133 feet per mile for 6 miles. Then a gradual slope, 56 feet per 
mile, for 10 miles, conducts to the Sweet Water, at an elevation of about 5,640 feet; distance 
from Red Buttes, 50 miles. The Sweet Water occasionally cuts through spurs, making cafions, 
(that of the Devil’s Gate being through granite;) but generally it is represented as rather 
open, and the immediate bottoms abound in soft grasses. The hills on either side are ‘‘rocky 
and bare.’’ At one of the head-branches of the Sweet Water we reach the South Pass, (eleva- 
tion 7,490 feet,) 124 miles from where we first struck the Sweet Water; average grade for 
the first 12 miles east of the summit, 22.5 feet, and the remaining 112 miles 14.7 feet per 
mile. The grades between these points would probably be somewhat undulating, but the 
present surveys do not afford the means of judging their extent. From the Red Buttes to 
the South Pass would be an expensive road, but it does not involve any difficult problem of 
engineering. Little need be apprehended from snows. The necessary fuel for working-parties 
