94 GEOLOGY. 



SOLFATARAS. 



Some volcanic mud springs or solfataras, to the north, in the Colorado Desert, have been 

 visited by Dr. J. Le Conte, of Philadelphia, in company with Major Heintzelman, U. S. A., 

 then commanding officer at Fort Yuma. The former gives an interesting account of his visit 

 there in Silliman's Journal, vol. xix, second series. No. 55, January, 1855. The existence of 

 these springs, however, was not altogether a new discovery of this party, but was well known 

 before to the natives of the country, who resorted to this locality for their annual supply 

 of salt. 



The other springs, southeast from Carrizo Creek, and not more than twenty miles from the 

 lower Colorado, were visited also, in 1853, by the same officer, accompanied by a small party. 

 The time this officer had chosen for his trip was about three months after a severe shock of an 

 earthquake, which had terrified the inhabitants of those regions on the 29th November, 1852. 



We are indebted to the liberal kindness of Major J. H. Thomas, the successor of Major 

 Heintzelman, in command of Fort Yuma^ for a glance at the manuscripts of the latter. The 

 description of the springs and what was known is, in substance, as follows: "There exists, 

 about forty-five miles below Fort Yuma, in the Desert between the western Cordilleras and the 

 Colorado, a pond, considered as an old orifice, which had been closed for several years." " The 

 first shock of an earthquake, in 1852, caused there a mighty explosion. Tlie steam rose a • 

 beautiful snowy jet more than 1,000 high into the air, where it spread high above the 

 mountains, gradually disappearing as a white cloud. 



" This phenomenon repeated itself several times in a diminishing scale. Three months later 

 I visited the place ; jets took place at irregular intervals, from fifteen to twenty minutes. The 

 effect was beautiful, as they rose mingled with the black mud of the pond. The temperature of 

 the water in the principal pond was 118° Fahr., in the smaller one 135° Fahr., and in one of 

 the mud holes, from which gases escaped, 170° Fahr. The air which escaped was full of 

 sulphurated hydrogen, and in the crevices crystals of yellow sulphur were found. The ground 

 near about was covered with a white efflorescence, tinged with red and yellow. On the edge of 

 a small pond crystals of sal ammonia, 1 to 5 inches long, were collected." 



CLAVIJERO'S ACCOUNTS OF LOWEE CALIFORNIA. 



Other important data bearing upon the geology of Lower California have been brought 

 before the public a long time ago by Clavijero, one of the missionaries in the southern part of 

 the peninsula. He mentions, in his Historia de la Antigua 6 baja California, (see Book I, 

 Chapter II,) " two lagoons near the mouth of the Colorado ; the red water of the former gave 

 rise to the river's name." The water is described as being very caustic, and so bad that it 

 causes instant swelling and ulcers, accompanied by a burning pain on any part of the body that 

 is brought in contact with it. The efiect is said to last for several days. The cause of these 

 bad qualities is likely to be a certain bituminous mineral issuing from the bottom of those 

 lagoons, where some navigators noticed it first in weighing their anchors. 



Besides these lagoons quite a number of interesting facts are mentioned by the same author. — 

 (See Book I, Chapter III, of his work.) Relating to the volcanic character of the shore skirting 

 the base of the Peninsular Cordilleras, the volcano of Mulege, near 27°, is mentioned. It was 



