84 
GEOLOGY. 
were thickly coated upon the upper side, and were placed in the collection, (No. 253.) An 
analysis of the crust, since the return of the Expedition, gave the following results: 
“ The aqueous extract contained only a small quantity of chloride of sodium, (salt.) In hot 
hydrochloric acid, the mass dissolved with strong effervescence, leaving a residue of silica and 
alumina. The solution contained: 
Lime, (carbonate,) chief constituent. 
Silica (soluble in acid.) 
Magnesia. 
Alumina and oxide of iron, traces. 
Phosphoric acid, trace. 
A distinct reaction for fluorine was obtained by heating the powdered mineral with fragments 
of marble and concentrated sulphuric acid in a dry flask ; passing the gas through aqua 
ammonia, evaporating this solution to dryness, re-dissolving, filtering and testing this filtrate 
evaporated to dryness by etching.” 1 
It thus appears that the principal constituent is carbonate of lime, and that soluble silica is 
also present. It is desirable that more examinations should be made of these incrustations, and 
a quantitative analysis is very desirable. 
The springs were estimated to he at least five hundred feet above the level of the Santa Anna, 
at the Mormon settlement, and thus nearly 1,618 feet above the sea. 
These springs are not the sources of the large stream of hot water first referred to. It takes 
its rise further eastward, nearer the mountain of San Bernardino. I regret that I could not 
visit its source, as the springs must be numerous, and of great volume and high temperature, to 
send forth such a large stream of water, retaining its temperature a long distance from the 
mountains. 
I was informed that there are several other localities of hot springs along these mountains ; 
and there are, no doubt, many that have not yet been discovered. 
The water of some of these springs contains alkalies and salts in solution. This was clearly 
shown by sticks or weeds that were partly immersed in the water, producing favorable condi¬ 
tions for continuous evaporation from the outer ends. These were thickly covered with salts 
in semi-crystalline crusts ; they dissolved readily in the mouth, giving a cooling sensation, 
similar to that produced by nitrates. The waters are supposed to possess medicinal virtues, 
and the Indians have been accustomed to resort to them for the cure of diseases. 
The large stream of hot water appears to be nearly pure, and is not disagreeable to the taste. 
It is used for drinking and cooking at the settlement several miles below. A bathing estab¬ 
lishment on a grand scale could easily be erected on the banks of this stream. I enjoyed a 
delightful bath in it, the desired temperature being easily obtained by ascending or descending 
the stream. The granite at the springs contains a large proportion of flesh-colored feldspar, 
distributed in veins. It appears to be much cracked and fissured; but this may be due to 
atmospheric decomposition alone. The rock around the springs is sensibly warm to the hand, 
at a distance of four feet or more from the orifices. There are no indications of erupted trappean 
or volcanic rocks in that vicinity ; nor is it at all probable that San Bernardino is volcanic. It 
has the appearance of granite. 
I left San Bernardino on the 6th November for the Cajon Pass, intending to join Mr. Smith, 
who was surveying it. The ascent to the entrance of the Cajon was very gradual, and there 
was no sudden rise of the ground. My road lay over broad fields where large crops of wheat 
2 This analysis was made at my request by Ur. J. D. Easter, of Washington, D. C.—See Appendix, Article VII. 
