These new strata have been formed by the water which runs on the surface of the earth, often changing situation and dispersing on every side. Part of these waters penetrate internally and flow across the clefts of rocks and stones; and the reason we meet with no water in high lands, no more than on the tops of hills, is, because all elevations are generally composed of stone and rocks, therefore to find water we must dig through the rock till we come to clay, or firm earth, on which these rocks stand, and we shall not meet with any water until the stone is pierced to the bottom: therefore, when the thickness of the rock, which must be pierced, is very considerable, as in lofty mountains, where they are often upwards of 1000 feet in height, it is impossible to dig to their base, and of course to have any water. There are even large parts of land where there is not any water, as in Arabia Petrea, which is a desert where no rain ever falls, where the scorching sand covers the whole surface of the earth, where there is scarcely any vegetable soil, where the few plants found are sickly, and where springs and wells are so very scarce that only five are reckoned between Cairo and Mount Sinai, and the water of them is salt and bitter. When the waters on the surface cannot find vent to flow they form marshes and fens. The most famous marshes in Europe are those of Muscovy, at the source of the Tanais; and those of Savolaxia and Enasak, in Finland; there are also some in Holland, Westphalia, and other low countries: in Asia are the marshes of the Euphrates, of Tartary, and of the Palus Meotis; nevertheless there are fewer of them in Asia and Africa than in Europe but America may be said to be but one continued marsh throughout all its plains, which is a greater proof of the modern date of the country, and of the small number of inhabitants than of their want of industry.