The depressions which have assumed a permanent form since the convulsions which formed them, have gradually filled with deposited soil, and, were the naturalist able to lay bare the primitive rock, he would discover that it exists in the shape of great concavities, without a trace of that evenness which now characterizes the surface. Eichwald has made it probable, by his personal observations, that the upheaval of Ararat and of the Armenian plateau on which this trachyte mountain rests, has driven the Caspian Sea back east of the flat steppe of Karabagh and Mogan, on the lower Aras, to the neighborhood of Bakoo. The water of that sea formerly extended to the confluence of the Bargashad, (called also Bergershat and Bergernet,) with the Aras, below Ireben. The traces of volcanic action there are decisively evident: the Caspian reached, before that action occurred, up what is now the valley of the Aras, as far as Ararat; and in many places south of Erivan—at Saliyan, in Shirwan, and elsewhere—salt beds of the most crystalline quality, forming whole mountains and whole belts of salt lakes at the confluence of the Aras and the Koor, demonstrate their formation in a former sea which once covered that region. The very recent upheaval of the Ural chain cannot fail also to have had an influence in contracting the dimensions of the Caspian hollow. Only two kindred depressions to this remain to be spoken of, which, though of not so great superficial dimensions, are of yet greater depth—the depression of the Jordan Valley and the bitter salt lakes on the Isthmus of Suez. These we must consider before we pass from the contrasts between highlands and lowlands to the transitions between them. The Depression of the Jordan Valley and of the Dead Sea. The nearest relationship to the Caspian hollow, displayed by any similar feature, is found near the heart of the Old World, in the comparatively diminutive and isolated valley of the Jordan, including the Dead Sea, whose absolute depth below the level of the ocean has been determined only within the most recent period. Many former travelers had noticed, in the deep gulf which holds the Dead Sea, and especially at its north end, near Jericho, a much greater degree of heat than elsewhere in Palestine, and the existence of many plants and fruits which they had met in the hotter climates of Arabia and India. The tree which yields the Mecca balsam flourishes in the oasis of Jericho; the product of the balsam of Palestine supplied the pin-money of Cleopatra. A number of German and English observers endeavored to solve the question of the depth of the Jordan basin—von Schubert, Russeger, von Wildenbruch, Moore, and Bake, later Symonds, and Lynch; de Berton and Russeger made the first barometrical observations at the Dead Sea, but they did not attempt to give more definite limits to their results than to assert that its surface is somewhere between 500 and 1100 feet beneath the ocean level.