230 AFRICA 



1.500 feet above sea-level, surrounded on all sides by the 

 edges of higher plateaus '. It was long described as one 

 colossal and unbroken stretch of equatorial rain-forest, 

 yet it appears to receive a rainfall that hardly exceeds 

 80 inches yearly. Perhaps the impression of boundless 

 selva which is recorded in the accounts of more than 

 one traveller is due, as on the Amazon, to the fact that 

 explorers seldom ventured far from the rivers, thus 

 having no opportunity to see the back-country. From 

 the edge of the plateau, for hundreds of miles up stream, 

 the main waterways are accompanied by wide belts of 

 true selva. This is true for the lower Sanga and the 

 Ubanghi up to its eastward bend, for the Congo up 

 to Stanley Falls, and for the lower Kasai. As in the 

 Amazon these broad strips on both sides of the main 

 streams are liable to permanent or temporary floods ; and 

 on the middle and upper sections of the rivers, the 

 selvas confine themselves to narrow fringes. The Congo 

 high forests are of the equatorial rain-selva type, like 

 the Amazon caaguapu in all its essential vegetative 

 features, much as the floras may differ. Oil and borassus 

 palms, which were present in the savana, continue to be 

 conspicuous in this region : rubber-trees and lianas are 

 found in abundance and heavily exploited. Among 

 other interesting trees may be noted the dragon-tree, 

 which is well represented in drier regions, the fig-tree, 

 rotang palms, ceibas, &c. 



The nature of the vegetation covering the tablelands 

 between the rivers has not as yet been satisfactorily 

 studied. In the Welle district, beyond the margin forest, 

 opens a park landscape of light woods and savanas ; the 

 Itiri forest, partly of the rain-forest type ; turns to a 

 lighter kind towards the east ; and in its middle course 

 the Kasai runs also through a variegated scenery of light 



