Page:Physical Geography of the Sea and its Meteorology.djvu/312

286 in considering marine fossils, changes of climates, the effects of deserts upon the winds, or the influence of mountains upon rains, or some of the many phenomena which the inland basins of the earth—those immense indentations on its surface that have no sea-drainage—present for contemplation and study.

532. The level of the Dead Sea.—Among the most interesting of these last is that of the Dead Sea. Lieutenant Lynch, of the United States Navy, has run a level from that sea to the Mediterranean, and finds the former to be about one thousand three hundred feet below the general sea-level of the earth. In seeking to account for this great difference of water-level, the geologist examines the neighbouring region, and calls to his aid the forces of elevation and depression which are supposed to have resided in the neighbourhood; he then points to them as the agents which did the work. Truly they are mighty agents, and they have diversified the surface of the earth with the most towering monuments of their power. But is it necessary to suppose that they resided in the vicinity of this region? May they not have come from the sea, and been, if not in this case, at least in the case of other inland basins, as far removed as the other hemisphere? This is a question which I do not pretend to answer definitely. But the inquiry as to the geological agency of the winds in such cases is a question which my investigations have suggested. It has its seat in the sea, and therefore I propound it as one which, in accounting for the formation of this or that inland basin, is worthy, at least, of consideration.

633. An ancient river from it.—Is there any evidence that the annual amount of precipitation upon the water-shed of the Dead Sea, at some former period, was greater than the annual amount of evaporation horn it now is? If yea, from what part of the sea did the vapour that supplied the excess of that precipitation come, and what has cut off that supply? The mere elevation of the rim and depression of the lake basin would not cut it off. If we establish the fact that the Dead Sea at a former period did send a river to the ocean, we carry along w4th this fact the admission that when that sea overflowed into that river, then the water that fell from the clouds over the Dead Sea basin was more than the winds could convert into vapour and carry away again; the river carried off the excess to the ocean whence it came (§ 267).

534. Precipitation and evaporation in the Dead Sea valley.—In the