In support of this theory we have the evidence of the salt-forming process that is now in operation in Southern Russia, America, and India. It is evident that at one time the low-lying country to the west and north of the Caspian Sea was part of that inland sea, and that, when its surface was contracted by shrinkage, the retreating water left behind it numerous swamps, which now form salt lakes, and tracts of intervening land which, in the dry season, are covered with a saline afflorescence. The large quantities of salt which, in ordinary seasons are deposited in these salt lakes, are collected by the Russian Government. In India there are many salt lakes, such as Lake Sambhur, in Rajpootana, which in the rainy season has a length of from fifteen to twenty miles, but in the dry season is only three or four miles long, the remainder of its course consisting of a succession of small salt pools alternating with stretches of salt-encrusted ground. In the great desert of Mongolia many square miles of country are spread with salt incrustations; and in America similar tracts are found which once formed the beds of considerable lakes. In Nevada, at the sink of the Carson River, is an area of five square miles which was once the bed of a salt lake. The famous Great Salt Lake, between the Wahsatch Mountains and the Nevadas in America, is the remains of a large inland sea which once covered the district, and should the climate become drier than it is now, the shrinkage, which went on for ages, will be resumed, and a huge salt deposit will be formed. The salt lakes in rainless districts soon dry up, and the salt, being quickly deposited, is almost pure, but such instances are not usual, and, in dealing with existing salt-depositing lakes, we find continual references to the salt and clay mixtures, or alternations of the deposits. Herr Cech tells us that the yearly layers of salt in Lake Elton are separated from one another by a layer of black mud; beneath the fourth layer is found black clay, and beneath this are further layers of salt of a more solid quality. Schleiden, in speaking of Lake Elton, says: “On this old salt is deposited a blackish mud layer (salt clay) which separates the salt from the next succeeding layer. In 1805 Göbel bored, in the very shallow lake, about 1½ miles from the shore. He found forty-two distinctly separated layers of rock salt, the uppermost from 1 to 4 inches thick, the lowest 9 inches thick. The deeper he bored the more solid the salt was, and the more pure. At the hundredth layer the salt was so hard that the iron tool broke.”