156 THE DESICCATION OF AFRICA. 



above the Bussa Falls, but the original outlet to the north 

 is not so clearly marked in the case of the Congo as it is in 

 the case of the Niger, at Timbuktoo. 



The crest of the coastal rampart is a range of hills„ 

 nearly half-way between Stanley Pool and the head of the 

 estuary, at Matadi, culminating in Mt. Ulia, 3,430 feet. From 

 this ridge the Congo originally flowed west to the sea, like 

 the rivers to the north, the Chiloango, the Nairi Quilo, the 

 Nyanga and others. The next great river to the norths 

 however, the Ogowe, has eaten back through the coastal 

 rampart and is making a bid for the inner drainage of the 

 continent. With two rivers equally vigorous, tapping the 

 same source, the river traversing the softer rocks wins. The 

 escarpment rises to 4,500 feet at Mt. Otombi, where the Ogowe 

 traverses it and generally, with this coastal rampart, it may 

 be taken that the higher the peaks, the more massive and more 

 resistant to the agencies of weathering they are. 



There is an interesting example of complicated river 

 capture in the Dscha tributary of the Sanga, a large river 

 that enters the Congo, just below the Ubangui confluence. 

 It rises in the south of the Cameroons and flows westwards, 

 as if to join a coast stream, the Nyong River, which is just 

 south of the Sanaga River. This Nyong River pierced the 

 coastal rampart and was stealing the waters of the interior, 

 when the great thief, the Congo, seized the prize, and the 

 Dscha now turns round in a semi-circle and flows eastwards. 

 Tributaries of the two rivers, the Sso of the Nyong River and 

 the Lobo of the Dscha, come very close to one another. The 

 struggle for territory is very keen in this area. The affluents 

 of Lake Chad, the original owners, are steadily retreating 

 northwards, as the Sanaga and other coast streams invade 

 their basins. The Congo, in turn, through its western 

 affluents, bringing every year more force to the head streams 

 as the lower river becomes cleared, is steadily filching from 

 the Lake Chad area and the conquered territory of the coast 

 streams. 



LAKE CHAD. 



Lake Chad lies 842 feet above sea-level. It is a sheet of 

 water that is rapidly diminishing from the filching away of 

 areas originally draining into it, by more vigorous streams 

 from the west and south. It is not a lake in the ordinary 

 sense of the word, with well-defined basin, but falls into the 

 category in which are Lake Ngami, the Etosha Pan, Lake 

 Leopold II., Lakes Debo and Faguibine on the Niger and the 

 Bahr-el-Ghazal on the Nile. That is to say, Lake Chad is 

 part of a river system that has been blocked up and is evidence 



