334 ANNUAL OF SCIENTIFIC DISCOVERY. 



in diameter. Within these cauldrons a bluish argillaceous paste is continu- 

 ally boiling with a dull murmur, emitting copious sulphurous vapors, and 

 huge bubbles, bursting, throw masses of mud to the height of several feet. 

 These kettles sometimes boil over, and the matter runs off in a slimy stream 

 toward the salt lake. This seems to have been the case recently, as we en- 

 countered the track of one of these streams, not yet dry, a mile from the Salse. 



The volcanic action was far more violent at some former period than at 

 present, as is proved by fragments of pumice scattered over the plain. Our 

 visit lasted only an hour and a quarter, owing to a deficiency of water. The 

 tempting objects in the vicinity, which would require many days for exami- 

 nation, could only be greeted with a farewell glance, and our horses' heads 

 were turned towards the nearest point at which a supply of water could be 

 obtained. 



For the first three or four miles after leaving the Salse, the plain presented 

 a smooth surface of sand and bluish clay, baked and fissured, and strewn 

 sparingly with volcanic cinders and obsidian fragments. Round holes 

 marked the escape of gas when the ground was softened by water. Soon 

 the plain became cut up with ravines three or four feet in depth, which Jose 

 said were the arms of " New River," which branched out before entering the 

 salt lake. The remains of a most luxuriant vegetation, now dead and dry, 

 proved the place to be a desert only for want of water. 



Thus ended a hurried trip to a most interesting spot in the midst of a no 

 less interesting district. The shells obtained were submitted to Dr. Trask, 

 and were found to consist of two species of Amnicola (A. protea and A. 

 longinqua, Gould), and the Physa (P. humerosa, Gould), before named. A 

 large bivalve was observed, but so thin and fragile that the specimens broke 

 to small pieces for the want of safe means of transporting them. 



The water from the volcano has the specific gravity of 1'075, and holds in 

 solution free boracic acid, with borates and a large quantity of chlorid of 

 sodium, and other salts. These matters would indicate the true volcanic 

 origin of the Salse, and but little doubt rests on my mind of its being so. 

 The evidence of former volcanic action in the neighborhood, and the testi- 

 mony of the boracic acid, establish its true character. The acid and its 

 compounds exist only in small quantities, but sufficient to be unequivocally 

 determined. Similar Salses exist some thirty or forty miles farther south. 

 One made its appearance during the earthquake of November 29, 1832, a 

 few miles below the line of the State. Two others exist in the same district, 

 as I was informed by a person who professed to have visited them. One is 

 represented as a single jet of steam and water from an opening, a yard in 

 diameter, situated in a plain of hardened clay. The other consists of several 

 pools of warm water, through which hot gas is continually escaping. 

 Another is again spoken of in the adjacent mountain, partaking of the true 

 volcanic character, emitting fire and smoke. I hope some one will soon have 

 occasion to examine these and other interesting localities at a season when 

 it will be practicable to pass a few days on the desert without danger of 

 perishing from thirst. 



The real character of this desert has not been generally understood. In 

 its present condition it is truly a desert. But only a portion, however, of 

 its immense area is condemned to irretrievable barrenness, viz., the part 

 covered with drifting sands. The greater part, from the constituents of its 

 soil, must be fertile in the extreme, and only wanting moisture to produce a 

 wilderness of vegetation. This is proven in the case of New River, while 



