The Salt Sea itself is enclosed on all sides by terraced hills, except towards the north, where it receives the waters of the Jordan. In rising gradually out of the ocean, the region appears to have rested several times at successive levels, and the sea left its mark in deposits of marl, gravel, and silt. Beyond the southern end of the Salt Sea the banks of the Ghor rise in the form of a great white sloping wall, to a height of about 600 feet above the plain, and are formed of horizontal courses of sand and gravel, resting on white marl and loam. This mural wall sweeps round in a semicircular form from side to side of the Ghor. The upper surface is nearly level (except where broken into by river channels), and from its base stretches a plain covered partly, over the western side, by a forest of small trees and shrubs, and partly by vegetation affording pasturage to the numerous flocks of the Arabs, who settle down here during the cooler months of the year. It is impossible to doubt that at no remote period the waters of the Salt Sea, though now distant some 10 miles, washed the base of these cliffs, and a rise of a few feet would submerge this verdant plain, and bring back the sea to its former more extended limits. From this position also, the white terrace of Jebel Usdum--“the salt mountain” where the Crusaders wrongly placed Sodom--is seen projecting from the sides of the loftier limestone terraces of the Judæan hills. Towards the east, similar terraces of whitish alluvial deposits are seen clinging to the sides of the Moabite hills, or running far up the deep glens which penetrate the sides of the great table-land. In these terraces, the upper surfaces of which reach a level of about 600 feet above the waters of the Salt Sea, we behold but the remnants of an ancient sea-bed, which must originally have stretched from side to side. Eight hundred feet higher than these terraces there are others composed of marl, gravel, and silt, through which the ravines of existing streams have been cut; and this indicates that the level of the Salt Sea stood at one time 100 feet higher than the waters of the Mediterranean stand now. _Origin of the saltness of the Dead Sea._--It has been generally recognised that the waters of lakes which have no outlet ultimately become more or less saline. Of these the most important in the old world are the Caspian, the Sea of Aral, Lakes Balkash, Van, Urumiah, and, lastly, the Dead Sea, or as it was originally called, “the Salt Sea.” “The Caspian,” says Professor Hull, “owing to its great extent and other causes, is but slightly saline; but that with which we have here to deal is the most saline of all. It is probable that the water of the ocean itself has become salt owing to the same cause which has produced saltness in the inland lakes, as it may be regarded as a mass of water without an outlet. The cause of the saltness in such lakes I now proceed to explain.