368 Whitney’s Geology of California, 
where water may be obtained for irrigation, and in a few such 
places the soil is very productive; but the region is a most in- 
hospitable one, and portions of it are absolutely unknown to 
civilized man. ? 
North of lat. 85°, to the Oregon line, the water that drains 
the eastern slope of the Sierras runs into closed basins, where it 
sinks into the sands, or forms salt lakes having no outlet to the 
sea. These form part of the Great Basin lying between the 
Rocky Mountains and the Sierra Nevada, To the south of this 
the Colorado river drains a region of similar physical characters. 
The southeastern part of the state, to the extent of perhaps 
80,000 square miles or more, lies in these deserts. ' 
Our geographical and geological information relating to this 
region is exceedingly limited. It is, however, sufficient to ren- 
der it certain that some of the data which have been furnished 
the public from official sources, on both regions, are of a very 
unreliable character. This much is known: that there are many 
chains of barren mountains, having in the main a north an 
south direction, with desert valleys between, some of which are 
sinks of streams; that at least one of these valleys, Death val- 
ley, is below the level of the sea; that portions of the Colorado 
Desert have been stated to be also lower; that the other valleys 
lie at various elevations up to 6500 feet, the altitude of Mono 
Lake; that the mountain chains are made up of volcanic, gran 
itic and metamorphic rocks; that the latter are probably of the 
same age as those of the auriferous veins of California, Triassi¢ 
and Carboniferous fossils having been found; that Tertiary 
rocks occur; and that the region has become very much drier 
since very recent geological times. It is certain that large areas 
now dry or oecupied by salt lakes of limited size were at a Jate 
period covered by lakes or inland seas that have gradually 
wasted away as the climate has grown more and more GT: 
These had their development perhaps at the time when those 
stupendous glaciers existed in the higher mountains, whos? 
traces are now so very abundant, especially in the high Sierra 
Nevada. A great number of most interesting questions ams 
in connection with this region, some of which must long remain 
unanswered; for others we have perhaps the data for their 8 
lation. w. H. B. 
The volume which has been here reviewed, and which, a8 the 
abstract presented has shown, is so rich in facts, is only a prelim- 
inary report on the Geology of the State, Professor Whitney has 
nearly ready another, giving the systematic geology with all it 
details and general conclusions; and he proposes to follow this 
With one or two on omical Geology, Mining and Metal- 
lurgy, in which department a large amount of material has bee? 
