TOPOGRAPHIC FEATURES OF THE DESERT BASINS. 59 
necessarily mean that they lack scientific interest. For instance, the 
small saline ponds of Alkali Lake are known to contain about 4 per 
cent of potash (K,O) in their total dissolved solids, and the Teels 
Marsh carries a number of the minerals which are associated with 
potash brines at Searles. It is quite possible that some of these 
smaller basins may prove to contain potash accumulations of rela- 
tively high grade, but the amount of the material is likely to be too 
small to warrant commercial exploitation. 
It is possible to eliminate two additional basins on special grounds. 
First, Bonneville, in spite of its great size, can be safely dropped from 
the list of possibilities. This is true on two grounds—previous over- 
flow and the areal geology of the basin. The overflow in itself might 
not be sufficient, for there has been a considerable period since the 
overflow ceased and time has probably been available for extensive 
potash accumulation. But the Bonneville Basin is set almost en- 
tirely in sedementary rocks, which can not reasonably be expected to 
yield any important quantity of potash to the drainage. Further- 
more, nearly all of the saline material accumulated within the basin 
is probably now in the Great Salt Lake, and the salts contained in 
this lake carry less than 2 per cent of potash (K,O). 
The last basin to be eliminated is the Otero, in central New Mexico. 
This was possibly once subject to overflow and is set almost entirely 
in nonpotash rocks, but its elimination is not based upon these facts 
so much as upon a detailed examination made of the basin specifically 
from the present point of view, and which resulted in a strongly 
negative conclusion.* 
The basins which remain may be divided into three divisions: 
(1) Those in which the known topographic and geologic conditions 
are fully favorable, (2) those in which some conditions are favorable 
and some adverse, and (3) those concerning which there is sufficient 
uncertainty to render classification doubtful and decision as to promise 
impossible. The basins of these three divisions are given in Tables 
Ii and III and IV, respectively. Of those in Table III the topo- 
graphic features are favorable in all cases but one—Owens. In this 
case the previous overflow into Searles introduces an unfavorable 
factor which has, however, been partially overcome by the length of 
time elapsed since this overflow ceased. At the present time the salts 
of Owens Lake contain approximately 2.25 per cent of potash (K,O). 
With the other basins of Table III the unfavorable factor is in all 
cases a lack of potash-bearing rocks in the drainage basin, the Che- 
waucan Basin being set almosz entirely in basalts and the others in 
Paleozoic sediments. 
Of the uncertain basins of Table IV, the Salton is doubtful, because 
of the difficulty of interpreting the influence of the Colorado River 
Free, Circ. No. 61, Bureau of Soils, U. S. Dept. of Agr. (1912). 
