The existence of such a mountain of salt was asserted by certain travelers many centuries ago, but the accounts which they gave of it were not generally believed, the spot being visited too seldom, and the accounts which were brought from it being too vague and imperfect to confirm sufficiently so extraordinary a story. Robinson, however, and other travelers who have, since his day, fully explored the locality, have found that the ancient tales were true. The ridge is very uneven and rugged, its summit and its sides having been furrowed by the rains which sometimes, though at very distant intervals, fall in this arid region. The height of the ridge is from one hundred to one hundred and fifty feet. The surface of the hill is generally covered, like that of other rocky ridges, with earth and marl, and sometimes with calcareous strata of various kinds, so that its true character is in some measure concealed from ordinary and casual observers. The mass of salt, however, which underlies these superficial coverings, breaks out in various places along the line of the hills, and sometimes forms perpendicular precipices of pure crystalized fossil salt, forty or fifty feet high, and several hundred feet long. The traveler who beholds these crystaline cliffs is always greatly astonished at the spectacle, and can scarcely believe that the mountain is really what it seems, until he has gone repeatedly to the precipice and broken off a fragment from the face of it, to satisfy himself of the true character of the rock, by tasting the specimen. The mountain extends for two or three miles along the shore, drawing nearer and nearer to it toward the south, until at last it approaches so closely to the margin of the sea, that the waters, when high, wash the foot of the precipice. Along the road which lies between the cliffs and the shore, and upon the beach, masses of salt are found, which, having been broken off from the heights above, have fallen down to the level land below, where they lie like common rocks upon the ground. Here and there ravines are found, forming little dells, down which small streams are constantly trickling; and, in some seasons of the year rains fall, and, dissolving small portions of the rock, flow with the solution into the sea below. Of course, what salt finds its way into the sea remains there forever, except so far as it is carried away by man--for the process of evaporation takes up the aqueous particles alone, from saline solutions. A very small annual addition is therefore sufficient to keep up the saltness of such a sea. It is supposed that this mountain is the source which furnishes the supply in this case. If so, the Dead Sea, geologically speaking, is simply an accumulation of the waters of the Jordan, formed in a deep depression of its valley, and made salt by impregnation from a range of soluble rocks, the base of which they lave. THE CAVERN. [Illustration: THE CAVERN OF USDUM.]