110 FIELD OF SALT — WELCOME RELIEF. 



to have been an ancient crater, forming three-fourths of an inverted 

 cone, open to the north-west, around which were sections of shales 

 and sandstones, very much contorted, and dipping in opposite 

 directions on opposite sides. The lower part of the cone was 

 filled with claystone. No volcanic rocks were found at the point 

 where we crossed these islands, but decomposed conglomerate and 

 alabaster occurred in considerable quantities. 



The first part of the plain consisted simply of dried mud, with 

 small crystals of salt scattered thickly over the surface. Crossing 

 this, we came upon another portion of it, three miles in width, where 

 the ground was entirely covered with a thin layer of salt in a state of 

 deliquesencce, and of so soft a consistence that the feet of our mules 

 sank at every step into the mud beneath. But we soon came upon a 

 portion of the plain where the salt lay in a solid state, in one un- 

 broken sheet, extending apparently to its western border. So 

 firm and strong was this unique and snowy floor, that it sustained 

 the weight of our entire train, without in the least giving way or 

 cracking beneath the pressure. Our mules walked upon it as upon 

 a sheet of solid ice. The whole field was crossed by a network 

 of little ridges, projecting about half an inch, as if the salt had 

 expanded in the process of crystallization. I estimated this field 

 to be at least seven miles wide and ten miles in length. How much 

 farther it extended northward I could not tell ; but if it covered the 

 plain in that direction as it did where we crossed, its extent must 

 have been very much ^greater. The salt, which was very pure and 

 white, averaged from one-half to three-fourths of an inch in thick- 

 ness, and was equal in all respects to our finest specimens for 

 table use. Assuming these data, the quantity that here lay upon 

 the ground in one body, exclusive of that in a deliquescent state, 

 amounted to over four and a-half millions of cubic yards, or about 

 one hundred millions of bushels. 



At two o'clock in the afternoon we reached the western edge 

 of the plain, when to our infinite joy we beheld a small prairie 

 or meadow, covered with a profusion of good green grass, through 

 which meandered a small stream of pure fresh running water, 

 among clumps of willows and wild roses, artemisia and rushes. 

 It was a most timely and welcome relief to our poor famished 

 animals, who had now been deprived of almost all sustenance 

 for more than sixty hours, during the greater part of which 

 time they had been in constant motion. It was, indeed, nearly 

 as great a relief to me as to them, for I had been doubtful 



