282 REVIEWS 
its volume is always above a certain minimum due to an artesian supply. 
The formations of the valley are the Santa Fé, composed of conglomerates 
and intercalated lava flows, and the Alamosa, a lake deposit, which, 
because of its sand beds interstratified with a series of blue clays, satisfies 
the necessary conditions for an artesian circulation. 
Most of the waters from the streams sink into the alluvial fans soon 
after they enter the valley, and this furnishes the water supply for the 
aquifers. If all the waters entering the valley were used for irrigation, 
it is estimated that 20,000-25,000 acres could be made productive. 
Most of the 3,234 wells in the valley are flowing, and a large number are 
used primarily for irrigation. They are described by localities; many 
records and twenty analyses of the waters are given. A peculiarity 
of the wells in the trough of the valley is the presence of small amounts 
of gas and brownish-colored water due, respectively, to vegetable accumu- 
lations and alkali deposits in the Alamosa formation, formed during an 
arid time when the lake was much shrunken. Springs are not uncom- 
mon, and of these several are of the thermal type. The accompanying 
topographic map shows the limits of the flowing wells, the gas field, and 
the colored waters. A. EL FE. 
The Origin of the Thermal Waters in the Yellowstone National Park. 
By ARNOLD HaGue. Science, N.S., XXXII, 1911, 553-68. 
The conditions of the region are such as could give rise to springs. 
The gases escaping from the waters and the substances held in solution 
could be derived from the rocks traversed, and they vary in composition 
according to the chemical nature of the rocks through which they ascend. 
For these reasons it seems that these thermal waters have a meteoric 
origin. Of interest is the clear explanation offered for considering a 
geyser but one phase in the development of some hot springs. 
A. FE. FE. 
Reconnaissance of the Geology and Mineral Resources of Prince 
William Sound, Alaska. By U.S. GRANT and D. F. HIGGINs. 
Bull. 443, U:S: Geol. Survey. 1910" Pp: 807 figss.o- pls; uz. 
The two divisions of the sedimentary rocks are the Valdez and the 
Orca groups, both of which are closely folded, and the latter lies uncon- 
formable on the former. Basic flows of greenstone, ellipsoidal in many 
places, are so intimately interstratified with the Orca, that they are 
discussed as a part of that group. Granitic bosses and dikes of diabase, 
