108 
GEOLOGY. 
surface was covered with a luxuriant growth of grass, and the mountains around were covered 
with vegetation. We passed the ruins of Warner’s adobe house, which it is said was burned 
by the Indians, and soon reached the camp of the main party, situated on a grassy plain, near 
the shore of a small pond or “ lagoon.” 
The valley is well situated for raising stock, and it is large enough to afford pasturage for 
immense herds. It is used for that purpose, and is a comfortable resting place for the droves 
of cattle and sheep that are brought in over the desert from New Mexico and Sonora. 
Warm Springs .—The thermal springs, generally known as “ Agua Caliente,” are situated on 
the slope of one of the ridges at the northeastern part of the valley. They have long been 
resorted to by Indians for bathing, and the cure of various diseases. The water boils up out of 
a granite ledge through a number of openings or cleavage fissures, and in one place it appears 
to have enlarged the opening, so that it has become nearly cylindrical. The water flows 
copiously from the different apertures, and the united streams give a volume of water about 
equal to what would be delivered from a two-inch pipe under a pressure of one or two feet. 
These openings are in a slight ravine, which appears to have been the bed of a brook that is 
now deflected from its course by a dam, built for the purpose by the Indians. In descending 
towards the spring, the odor of sulphuretted hydrogen is at once perceptible ; and a slight 
cloud of steam rises from the water. The temperature of the Avater at the different openings 
was taken, and the following are the results : Time, 9 a. m., November 30. 
1st or principal spring_temperature, F__142° 
2d spring, “ 141° 
3d spring, “ 140° 
4th spring, “ 140° 
5th spring, 10 feet distant, “ 136° 
Stream below the springs, “ 130° 
Stream above the springs, “ ...... 58° 
Temperature of the air, “ 74° 
Bubbles of sulphuretted hydrogen were constantly escaping, and the water was highly charged 
with it, and had an acid taste that was quite agreeable. There was only a slight incrustation 
or deposit on some of the rocks. On those near the spring I found a slight yellow film, thickest 
at the edge of the water in the quiet pools ; this was afterwards found to consist almost wholly 
of sulphur. A small jet of steam or air was constantly issuing from a crevice near the main 
spring, producing a slight hissing sound like steam from a leak in a boiler. 
The granite at this locality is compact and hard ; it has a coarse grain and texture, and a 
light-grey color. The proportion of mica and hornblende is small, but they are uniformly 
distributed in fine grains. 
The mass is traversed by cleavage planes or fissures in two or more directions, but this regu¬ 
larity or parallelism was not sufficiently distinct to enable me to determine the direction or angles 
of intersection. Some of the principal ones trend north 9° east to north 12° east, (magnetic.) 
Higher up in the bed of this brook, on the side of the mountain, the granite appeared nearly 
the same as that just described. I observed, in addition, that it contained lenticular, horn- 
blendic, and micaceous masses, similar to those seen in the granite of the Sierra Nevada, at the 
Tejon Pass. The color and texture of this granite is similar to that at the divide, and it has a 
trend north 5° west. 
All these granite ridges are well wooded with several varieties of oak, and in some places a 
thick growth of shrub oaks. The soil of the valley is formed of the materials of the granite, 
and the luxuriance of the grass and vegetation testifies to its good quality. 
