It may roughly be divided into four zones: - (1) the small coast zone west of the Crystal Mountains, through which the Congo breaks in a succession of rapids to the Atlantic; (2) the great central zone, described below; (3) the smaller zone east of the Mitumba range (including the upper coursesof some of the Congo tributaries which have forced their way through the mountains), and west of Lake Mweru and the upper course of the Luapula; and (4) an area which belongs geographically to the Nile valley.
Flowing first south, it afterwards turns north through Lake Mweru and descends to the forest-clad basin of west equatorial Africa.
Besides the East African lakes the principal are: - Lake Chad, in the northern area of inland drainage; Bangweulu and Mweru, traversed by the head-stream of the Congo; and Leopold II.
All, except possibly Mweru, are more or less shallow, and Chad appears to by drying up. The altitudes of the African lakes have already been stated.
In southern Katanga a tribe called Bassanga are cave-dwellers, as are also the Balomoto, who live in the Kundelungu hills west of Lake Mweru.