Page:Africa by Élisée Reclus, Volume 3.djvu/168

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WEST AFRICA.

force of the current stems the tidal stream, so that the water is quite fresh at Saint Louis, and even penetrates into the sea, where it may be distinguished by its yellowish colour amid the liquid blue of the surrounding ocean. At this season the discharge is certainly several thousand cubic yards per second, for the stream not only fills the broad and deep fluvial bed, but also overflows both banks, flooding numerous lateral lagoons, or "false rivers," which mark the course of former channels. The inundations even attain an exceptional development about every four years, when in its lower course the river assumes the aspect of a great inland sea from 12 to 15 miles wide.

Towards its mouth the Senegal ramifies to the right and left into numerous channels or tortuous lagoons, here called "marigots," a term also wrongly applied to the permanent tributaries and to the brackish lacustrine basins on the coasts. During the floods these lagoons serve to relieve the overflow, which in the dry season is here husbanded as if in artificial reservoirs. The two largest of these side

Fig. 50. — Floods of the Senegal.

lagoons are disposed on the right and left near the point where the Senegal bends southwards to skirt the coast dunes. The Cayar or Khornak basin on the north or right bank is some 12 miles long, with three outlets to the main stream; while the southern, variously known as the Guier, Paniéful, or Merinaghen Lake, occupies with its affluent, the Bûnûn, a winding valley about 90 miles in length. Even in the dry season this navigable basin retains some water, which attracts wild animals from all directions.

The Senegal Delta.

The delta, some 600 square miles in extent, forms a labyrinth of islands, islets, and marshy banks, separated by streams, channels, and stagnant waters, changing their form and depth with every inundation. The whole of this low-lying tract, half lacustrine during the period of floods, is sharply limited westwards by a