The most important river, both from the length of its course and the volume of its waters, is the Shellif, which, rising in the northern slopes of the Djebel Amur, flows first north and then west till it emptiest itself into the Mediterranean near Mostaganem after a course of 370 miles, during which it receives numerous tributary streams. The Seybouse is formed by the union of several small streams in the interior of the province of Constantine, south-east of the town of that name, and after a course f about 120 miles falls into the Mediterranean near Bona. The Summan, which contains the greatest body of water after the Shellif, rises in the interior of the province of Algiers near Aumale, and pursues a generally north-east direction to its mouth near Bougie. The Rummel, formed of several small streams south of the town of Constantine, passes that town and pursues a north-west direction to the sea. Among the less important rivers which empty themselves into the Mediterranean are the Harrach, Isser, Mazefran, Tafna, and Macta. Besides these, there are a number of streams in the interior, but they are less known and are generally dry except in the rainy season.
Algeria abounds in extensive lakes and marshes. Of the lakes in the northern part of the country, near the coast, the principal are, - the Fezara, 14 miles south-west of Bona; the two lakes Sebkha and ElMelah, south of Oran; the three small lakes in the immediate vicinity of Calle, and several others. In the southern part so of the country are the extensive lakes of Chott-el-Harbi or Western Chott; the Choptt-el-Chergui or Eastern Chott; the Zarhez-Gherbi and the Zarhez-Chergui; the Grand S ebkha-el-Chott, and a number of others. These are mostly dried up in summer, leaving a thick stratum of salt. Many of the marshes, especially in the neighbourhood of the larger towns have been drained by the French, and the climate has thus been rendered more salubrious. There are also a number of warm mineral springs, containing principally salts of lime, which are used with success by the Arabs in several kinds of disease.