THE TANGANYIKA HAS NO EFFLUENTS. 



141 



with large shingle, gravel, comminuted shells, and ma- 

 rine exuviae, with a fringe of drift formed by the joint 

 action of wind and wave. Beyond this is a shelving 

 plain — the principal locality for cultivation and settle- 

 ments. In some parts it is a hard clay conglomerate ; 

 in others, a rich red loam, apparently stained with oxide 

 of iron ; and in others sandy, but everywhere coated 

 with the thickest vegetation extending up to the back- 

 ground of mountains. The coast is here and there 

 bluff, with miniature cliffs and headlands, whose for- 

 mation is of sandstone strata tilted, broken, and distorted, 

 or small blocks imbedded in indurated reddish earth. 

 From the water appeared piles of a dark stone re- 

 sembling angular basalt, and amongst the rock-crevices 

 the people find the float-clay, or mountain meal, with 

 which they decorate their persons and the sterns of 

 their canoes. The uncultivated hill summits produce 

 various cactaceae; the sides are clothed with giant trees, 

 the mvule, the tamarind, and the bauhinia. On the 

 declines, more precipitous than the Swiss terraces, 

 manioc and cereals grow luxuriantly, whilst the lowest 

 levels are dark with groves of plantains and Guinea- 

 palms. 



A careful investigation and comparison of statements 

 leads to the belief that the Tanganyika receives and 

 absorbs the whole river-system — the net-work of streams, 

 nullahs, and torrents — -of that portion of the Central 

 African depression whose water-shed converges towards 

 the great reservoir. Geographers will doubt that such 

 a mass, situated at so considerable an altitude, can 

 maintain its level without an effluent. Moreover, the 

 freshness of the water would, under normal circum- 

 stances, argue the escape of saline matter washed down 

 by the influents from the area of drainage. But may 



