Explorations and Surveys for the Pacific Railroad. 81 



among broken ranges of mountains; its length about three 

 hundred miles. It is without affluents, and terminates near the 

 foot of the Sierra Nevada in a marshy lake. It has a moderate 

 current — is from two to six feet deep in the dry season, and 

 probably not fordable anywhere below the junction of the two 

 streams during the melting of the snows. The valley varies in 

 width from a few miles to twenty, and, excepting the immediate 

 river-banks, is a dry, sandy plain, without grass, wood, or arable 

 soil. Its own immediate valley (bottom) is a rich alluvium, cov- 

 ered with blue grass, herds-grass, clover, and other nutritious 

 grasses, and its course is marked through the plain by a line of 

 willow. 



Of the three lines from the Humboldt river to the foot of the 

 Sierra Nevada, the best is that by the Noble's Pass road, as it 

 avoids the principal range of mountains crossed on the line fol- 

 lowed a few miles south. The line followed crosses two ranges 

 of the general character of the Basin mountains, and reaches the 

 foot of the Madelin Pass of the Sierra Nevada [lat. 41°], on the 

 west shore of Mud lake, in a distance of 119 miles, and at an 

 elevation of 4,079 feet above the sea. 



In this latitude, the Sierra Nevada was found to be a plateau 

 about 5,200 feet above the sea, 40 miles in width from east to 

 west, enclosed at these limits by low mountains, the summits of 

 the passes through which are 400 and 500 feet above the base. 

 The plain is covered with irregular spurs, ridges, and isolated 

 peaks, rising a few hundred feet, limiting it in a north and south 

 direction sometimes to a space of a few hundred yards, and at 

 others to that of ten miles. These spurs, &c, on the eastern 

 portion of the plateau, are sparsely covered with cedar ; on the 

 western, heavily covered with pine. 



There is no drainage from this plain, the waters of a few 

 small streams and springs forming grassy ponds upon its surface. 

 In its general features it is similar to the Great Basin, excepting 

 that as more rain falls upon it, the vegetation is comparatively 

 luxuriant. 



There are two routes by which this plain may be reached from 

 the Great Basin, and the descent made to the Sacramento river. 

 That by the Madelin Pass, the more northern, is most probably 

 the better of the two, and is the only one necessary to be con- 

 sidered. Leaving Mud lake, it ascends by the valley of Smoky 

 creek for three miles, through a narrow gorge (from 100 to 150 

 yards wide) in an outlying spur of the Sierra Nevada. 



After this, the route is over more open ground, varying, in 

 degree, to the summit of the passage through the eastern ridge 

 bounding the Sierra Nevada plateau. The pass is thus far of a 

 very favorable character — the length of the ascent is 22*89 miles ; 



SECOND SERIES, VOL. XXII, NO. 64. — JULY, 1856. 1 1 



