Page:Africa by Élisée Reclus, Volume 1.djvu/186

 gypsum cliffs, here and there intersected by wadies. Their summits are crowned with feathery dum palms, and from their sides flow perennial springs. A verdant circle thus surrounds this desert waste, where nothing is visible but a few acacias and brushwood. At some distance from the cliffs are saline efflorescences, which become gradually solidified towards the middle of the plains, where they acquire the consistency of slabs some two feet thick. ere and there they present a greyish tesselated appearance, the interstices being filled with dazzling white crystals. At the lowest level of the depression, between the Ansali promontory and Mount Ortoaleh, are collected the waters of Lake Alalbed, or Allolebed, whose size varies according to the quantity of water brought down by the torrents. Its mean depth is said scarcely to exceed 40 inches. The dessication of the old bay of

Ansali may be explained by a gradual upheaval of the coast west of the Red Sea, as well as on the east side in Arabia. The coral banks and recent shells found at the north of the plain attest the presence of marine waters on the now upheaved depression between the plain of Ragad and Auwakil Bay. The rivers flowing from the Abyssinian chain are not sufficiently copious to repair the loss by evaporation, and thus the old lake, formerly of some extent, has gradually become a shallow swamp. The Taltals, who inhabit the surrounding district, assure the Abyssinians, possibly to protect themselves from their visits, that the lake occasionally "walks away" from its old bed in search of a new one; and woe to the caravans overtaken by this sudden inundation! Besides, even at some distance from the lake, travellers run the risk of sinking into the treacherous soil, and whole companies of men and beasts are said to have thus disappeared.