THE DESERT PORTION. 251 
Mumboldt; the rim separating these basins being here but 
5360 feet aes the Lake.* 
‘The inland or Great Basin region of North Adc extends 
om the dividing ridge of the Wahsatch Mountains to the 
Summit of the Sierra Nevada, 721 miles by the railroad. It 
is a vast desert, considerably larger than France, covered with 
hort volcanic mountain ranges; it possesses a fertile soil, but 
suffers from an insufficient rain-fall ; none of its scanty streams 
enter the sea, but each discharges its waters into a little lake 
ad remains shut up within its own independent basin. Rich 
silver mines are being discovered, year by year, all over the 
sin region, and the yield from them already equals in value 
that of the gold-fields of California. It contains three towns, 
alt Lake City, Austin, and Virginia City; the railway 
‘ asses within thirty-five miles of the first, 100 miles of the 
4 ond, and sixteen only of the last. 
_ The railroad follows the valley of the Humboldt River, 
rom Humboldt Wells, north-west of Great Salt Lake, where 
t rises, to Humboldt Lake, not far distant from its “ sink” 
(as ance 280 miles), and reaches the base of the Sierra 
Nevada 100 miles farther westward. 
From the Truckee River, elevation 5,866 feet, to the sum- 
of the sierra, the distance is fourteen miles, and the 
nt 1,176 feet, making an average grade of 84 feet per 
. From the summit, elevation 7,042 feet, to Colfax, on 
western side of the range, the distance is fifty-one miles, 
the descent 4,594 feet, or an average grade of over 90 
per mile. In fact, the Central Pacific Railroad, starting 
the Sacramento, only 56 feet above the level of the sea, 
s the summit of a mountain ridge exceeding 7,000 feet 
05 miles. Here all the engineering difficulties of the 
: * Elevation of Great Salt Lake, 4,290 feet. 
