GEKEEAL EEPOBT. 
XV 
but little above , the level of the lake. The lake itself is for the most part 
very shallow, in no place over hftj feet in dej^th, the waters a concen- 
trated solution of salt. As with all these sheets of water the shore-line and 
consequent area vary greatly in different years. 
The intermediate ranges of the Basin are very similar to each f)ther 
in character. They vary in altitude from one to six tlionsand icet above 
the valleys, culminating in occasional peaks scarcely evci- so rugged that 
they cannot be ascended from some direction upon mules. Tlu'y '<ire cut 
up by numerous ravines or "canons," which are narrow, very rai'ely wilh an 
acre of intervale or surflice approaching to a level, the side's sometimes rocky 
or precipitous, more frequently sloping to the summits of I he lateral ridges. 
In geological structure these ranges are more or less complicated, sliowing 
rocks of all ages from the azoic to the glacial period, here metamor[)hic rocks, 
quartzites, slate, and limestones, there an outburst of granite or syenite, vol- 
canic rocks of often the most diverse and picturesque colors, or broad table- 
lands of lava overflow. The erosion and decomposition of these various 
rocks have filled the valleys to a monotonous level with a detritus of gravel, 
sand, or silt, and given to them that accuuudation of alkaline salts which is 
so marked a pecidiarity of the country. 
With few exceptions also these mountains are for most of the year 
wholly destitute of water, with but small rivulets in the princijial canons, 
frequently with only scanty springs here and there at their l)ases, irri- 
gating a few scpuire yards of ground. Even where the mountain supply is 
sufficient to send a stream into the valleys it is usually eilher soon entirely 
evaporated, sinks into the porous soil, or becomes demoralized with alkali 
and is ''lost" in the mud of the plain. The lowest jjortiou of nearly every 
valley is occupied by some extent of alkali flat, whei-c in Ihe wiuter season 
the water collects and the soflencd clay-like mud is bollondess and im- 
passable. As tlie moisture evaporales under Ihe heat of coming summer the 
level naked surface becomes hard and pavenicnt-like, or coveicd with a 
snowy incrustation or deposit of salt or carbonates. The sprimrs and wells 
even are often more or less saline, and thermal sprinij-s are not rare. 
The chief exceptional ranges in nortliern Xcva(hi, ^\•hich from their 
greater altitude receive heavier snowfalls in winter, retained through tlie year 
in greater or less quantity in the more sheltered depressions of the higher 
peaks, and which in summer are subject to more abundant rains, are ihe 
