222 THE GEOLOGY OF BRITISH EAST AFRICA part hi 



The Geographical Zones of British East Africa. — In the 

 Geographical fournal it was pointed out that British East Africa 

 may be considered to consist of seven zones or belts, running 

 north and south approximately parallel to the coast.-' 



The first of these is the coastal plain, known to the 

 Suahili as the " Temborari." In some parts of East Africa 

 this is a wide tract of malarial country, but in most of the 

 British dominions it is narrow, and can be traversed in one or 

 two marches. It consists of a low-lying plain, formed of raised 

 coral reefs and old sea-beaches, and is generally covered by a 

 soil formed of wind-borne sand. On the seaward margin there 

 is a line of dunes, which are sometimes 150 feet in height. 

 This zone is deeply indented by estuaries, which, as they are 

 followed inland, are found to branch repeatedly ; some of the 



,,. • Primitive 



^'- °f Mountain 



... Volcanic Chain Axis P 



W. '^' 



Nyanza ftangatan Hift Rangatan /\ Rangatan \ Nyika Plateaux 



Valley / \ ; Temborari 



I / \ '• : or 



J "^ V 1. ': Coast Plain 



Fig. II. — Section across British East Africa. 



small creeks unite with those of an adjoining estuary, and thus 

 islands are cut off from the mainland. The shores of the 

 estuaries are mud flats, on which grow dense jungles of man- 

 groves. The flats are uncovered at low tide, and the decom- 

 position of the vegetation and dead marine animals left upon 

 them causes the malarial exhalations which are the bane of 

 the coast. 



The next zone — the Foot-hills — is also narrow, and is 

 entered to the west of Mombasa at Chamgamwe, at the summit 

 of a steep slope that rises 200 feet above the shore. From 

 this point there extends westward an undulating plateau covered 

 with woods, groves of palms and plantains, orchards of mango 

 and papaw, and fields of dry rice, maize, and dhurra. This 

 district is the granary of Mombasa, as it was in the fourteenth 

 century at the visit of Ibn Batuta. The foot plateau is not 



^ J. W. Gregory, " Contributions to the Physical Geography of British East Africa," 

 Geog. lourn. vol. iv. (1894), pp. 293-297. 



