xiv 
BOTANY. 
The main depressions witliin this region are two, one at the base of the 
Sierras at a level of about 3,850 feet above the sea, into which flows all of 
(li-ainage there is from the whole northern half of Nevada and from the 
eastern sh)pe of the Sierras, the other the ''Great Salt Lake Basin," at an 
altitude 400 feet greater, close upon the base of the Wahsatch and receiving 
the waters from that range above latitude 40° and iVoni the northeastern por- 
tion of the Ilintas. Into the first flow the Truckee, Carson, Quinn's, and 
Humboldt Rivers. The Truckee is a clear cold stream, which issues from 
Lake Tah oe in the Sieri-as and after a rapid descent breaks through the 
VirLjiiii.i ^Fountains and turning north soon emj^ties into Pyramid and 
Winneniucca Lakes. These are much the deepest of all the lakes of the 
])asiii, Ix'ing heinnied in by nioimtains, and are moderately saline. The 
Carson River also rises in tlie fSierras, farther to the south, but after leaving 
the base of the mountains is a less rapid stream and gradually becomes 
s(Hne vhai alkaline. Inclining more to the eastward it forms a small 
shallow Iak(» on the border of Carson Desert, and thence issues in a number 
of devious channels, and is finally spent in an extensive sink " or alkaline 
mud phiin of some twenty or thirty miles in diameter. Of a like character are 
the " ^[ud Lakes," lying north of Pyramid Lake and fed by Quinn's River, 
which has its source in southeastern Oregon. Beyond the limits of the sur- 
vey to the south are Walker's and some other smaller lakes, supplied by 
streams from the Sierras, but all strongly sahne. 
From this western depression the general level of the country rivses 
gradually eastward very nearly to the Ijorder of Xevada, where the 
valleys have an altitude of al^out G,000 feet. Here in the northeastern part 
of the State the Humboldt River takes its rise, by far the most important 
river of the basin, not only as the longest but as opening a passage for 
300 miles to the Central Pacific Railroad through the mountain ranges that 
would otiierwise have proved a serious obstruction. It is nowhere a large 
stream, re(!eives very few affluents, and in some parts of its course is very 
tortuous. It at length spreads out into Humboldt Lake, shallow and sub- 
alkaliiu^ and from this tlu^ little remaining surplus water finds its way in a 
manner similar to the Carson River into the same sink. 
The descent of 2,000 feet iVoni i:asterii Nevada into tlie Great Salt 
Lak<^ r»asin is alnidst iuunediate, nearly tin; whole northwest(M-n portiim of 
rtah being an alkaliiu^ desert, broken by fewer mountain or hill ranges and 
