OCR Text |
Show 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. Grossing 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 unbroken 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, averaged1 from one- half to three- fourths of an inch in thickness, 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 |