RIVERS AND SPRINGS—RETENTIVE STRATA OF CLAY. 993 
to ten inches deep. The water was clear and cold, and flowing rapidly over a bed filled with 
boulders as large as the head. It was evident, from the character of the channel, that at 
certain seasons a great body of water flows down to the slope and is spread out upon it. 
Cotton-wood Creek is of much less importance, and at the time of the examination was not a 
flowing stream ; but the channel gave evidence of occasional torrents of great volume. 
The stream called Agua de Tomaso, or Agua de Tio Mes, which is generally represented on 
the maps as a tributary of the Mojave, is merely a spring of bitter water, and does not form a 
stream over one hundred yards in length. 
Nearly all of the streams which descend from the mountains into the Basin are confined to 
the cañons or channels of the slope, and they do not extend far out from the mountains or 
spread out over the slopes. "Those which are of great volume, or are swollen by sudden rains 
orthe melting of snow, and thus reach the open plain of the slope, become divided up into 
numerous shallow beds, and are soon completely absorbed by the sand. This was well exhibited 
by Johnson's River, and others. The action of these rivers upon the slopes of the Basin, and 
the formation of temporary lakes at the base of the slopes, has already been considered. 
Springs.—Several springs were found in different parts of the Great Basin, but generally in 
the vicinity of the Lost Mountains. It would appear that the greater part of the water which 
is supplied to the Basin by the rivers or by rain sinks immediately away, far below the influence 
of the dry atmosphere, in the deep and loose gravelly materials which form the slopes and 
occupy its depressio s. This water may not reach the bed-rock of granite, but may pass 
through the porous strata until intercepted by an impervious stratum, and be thus collected and 
retained in underground reservoirs. From these stores the water occasionally reaches the sur- 
face and forms springs. From the nature of the surface of the Basin, and the uneven character 
of the underlying rocks, we may venture to conclude that there are many springs throughout 
its extent. The short excursion made by Lieutenant Williamson and myself, from the Tejon 
towards the Mojave, resulted in the discovery of no less than five springs within a linear distance 
of twenty-five miles. These springs were well known to the Indians, and we were guided to 
some of them by a Mojave, who probably had often visited them in his journeys to and from the 
settlements south of the Cajon Pass. : 
At the time of our visit to these springs all the low grounds were completely dry, and there 
did not seem to be a possibility of finding water in such barren and desert-like regions. At a 
distance, however, of about eight miles from the last water of the Tejon Pass, a green spot of 
grass, six or eight yards in diameter, was found, and in the centre a spring of cool, delicious 
water. Its temperature was 64°, and the air 90°. The ground was raised about it in a slight 
mound, which is probably a result of the accumulation of vegetable matter and sand. It is 
about one mile distant from the base of the first Lost Mountain, and, by the aneroid barometer, 
is 1,000 feet below the margin of the Basin-slope. Numerous masses of compact white clay, 
ànd an unusual amount in the soil, indicated the proximity of underlying clay beds. There 
was no outcrop of strata, but it is probable that they rise near to the surface. : 
Six miles further east, another spring rises at the base of another rocky ridge. It is not, 
however, in the lowest ground, as it is at the upper margin of the long slope flanking the ridge. 
It forms a pool about six feet in diameter, containing an abundance of good water, and a small, 
trickling stream flowed from it for a few yards. This spring had been much resorted to by 
Indians, as the bones of horses and mountain sheep were found around it. Three other springs, 
similar to those described, were found, at intervals of from six to ten miles, at different points 
