114 Tht American Geologist. August, 1894 
The investigations relative to irrigation include (1) the systematic 
mapping of the arid regions in order to show the location and altitude 
of the irrigable lands, their position with regard to the rivers from 
which the water is to be obtained, and the area, altitude, andcharacter 
of the catchment basins from which the rivers receive their waters; (2) 
measurements of the amount of water flowing in the mosl important 
streams, with computations of the quantity available fur each day of 
the year, either for immediate irrigal ion or for storage purposes; and (3) 
engineering examinations of such localities as the knowledge of the to- 
pography and of the water supply seem to indicate ;i s favorable for 
greal irrigation developments. At these places careful surveys are 
ma ile to tesi the practicability of diverting the waters of some river and 
carrying them out by large canals to command extensive areas of arid. 
though fertile, land, or of holding the Hood waters in greal reservoirs so 
that the flow of the streams can be increased in time of drought. These 
surveys are in each case carried to the degree of testing the feasibility 
of the schemes from a financial standpoint. This report gives descrip- 
tions of 147 reservoir sites, with accompanying hydrographic data, illus- 
trated by maps and diagrams. During the year here reported 21,475 
square miles were mapped for this department of the survey, in the 
states of Montana. Idaho. Kansas. Colorado, Nevada. California, Texas, 
and New Mexico. The total areas segregated for the reservoir sites are 
165,932 acres; and the areas of the reservoirs, at their proposed stages 
of high water, amount to 108,350 acres. Their contents would be ap- 
proximately 2,847,815 acre-feet, which, allowing two feet of water for 
irrigation during the growing season, will supply half as many acres. 
This is nearly equal to the irrigation crop area shown by the census of 
1890 in Montana. Idaho. Wyoming, Utah, Nevada, Mew Mexico, and 
Arizona. Most of the sites selected for reservoirs are high in the moun- 
tains at elevations of 5,000 to 10,000 feet, where the loss from evapora- 
tion will he less than it would he down nearer to the irrigated lands. 
Mr. Wilson's paper on irrigation engineering in India gives abundant 
details relating to economy and permanence which have been there de- 
veloped through long practice, whereby American engineers may reap 
the results of much cosily experience. He shows the benefits, financial 
and political, derived from tin- canals of India, and points out how in 
many localities the topography, climate and water supply resemble 
those of our arid West ; but with our lower mountain ranges and smaller 
rivers it is not needful nor possible for us to construct so large canals 
and reservoirs. w. r. 
The Origin and Katun of Soils. By Nathaniel Southgate Shalek. 
Pages 218-345; plates n-xxxi. and figures 1-27. (Accompanying the 
Twelfth Annual Report, U. S. Geol. Survey.) In this admirably illus- 
trated memoir Prof. Shaler treats, in a style suited to ordinary unpro- 
fessional readers, the interesting conditions of soil formation: diverse 
kinds of soils; causes-of the treelessness of prairie areas: the beneficial 
action of earthworms, ants, the larger burrowing animals, and deeply 
