Algerian river. The sources of the Sherf, its chief headstream, are intermingled on the Aïn-Beide plateau with those of the Tunisian Mejerda and its affluent, the Wed Meleg. At a former geological epoch the plain now traversed by the lower Seybouse formed a marine inlet, of which the shallow Lake Fetzara is a remnant. Between the sea and the eastern Wed-el-Kebir, at its mouth known as the Mafrag, the town of La Calle is encircled by a girdle of three lakes — the Guera-(Guraa)-el-Melah, or "Salt Lagoon;" the freshwater Guera-el-Ubeïra draining during the floods to the El-Kebir; and the Guera-el-Hat, or "Fish Lagoon," which reaches the sea through the sluggish and sedgy El-Mesida.
Except the narrow strips drained by the Upper Shelif and the Mejerda, with
its tributary, the Meleg, the whole of the Algerian plateau region is comprised within the region of closed basins, which were formerly united, and which would again be connected in one system with a more abundant rainfall and less elevated temperature. The larger basins take the name of shofts, less extensive freshwater or brackish depressions being known as dhayas, while the term ghedir is applied to muddy swamps or meres. Most of the shotts are encircled by rocky banks or cliffs 50 or 60 feet high in some places, but now separated from the lacustrine waters by intervening saline beaches or strips of crumbling gypsum mixed with sand. Such is the aspect of the Shott Gharbi, or "Western Shott," on the Maroceo frontier. The Shott Shergin ("Eastern") has a total length of nearly
