﻿Vol. 6 1.] NORTH-EASTERN TERRITORIES OE THE CONGO FREE STATE. 643 



II. Physical Features. 



A large extent of the Uelle district is very densely wooded, being 

 part of the great Equatorial Porest, which stretches as far as the 

 Bomokandi and Uelle rivers. North of these, the country consists 

 generally of vast plains covered with grass and scrub, intervening 

 between broad valleys, into which the forest sends out prolongations 

 from its main area : the forest-growth naturally following the water- 

 courses. The country reaches its greatest elevation towards the 

 east, at the Nile-Congo watershed, where it attains an elevation of 

 3300 feet, and, in places, as much as 4000 feet ; on the south-east, 

 a wide area is hilly and even mountainous. In the north-eastern 

 part, close to the Bahr-el-Ghazal, appears a group of hills of some 

 importance, with Mount Bundukwa, Mount Yambili, and several 

 smaller elevations. 



Westward, the country becomes gradually lower and forms a 

 series of broad undulations which produce hardly any visible effect 

 on the contour. Through this monotonous country pierce, in 

 places, groups of isolated hills, such as Mount Angba, on the Uelle, 

 near Amadi ; Mount Madjema, near Poko ; Mount Tena, on the 

 Bomokandi ; and others of minor importance. 



Close to Libokwa, a ridge of granite running north-west and 

 south-east stretches quite close to the southern bank of the Uelle, 

 and extends towards the Palls of Lipodongu on the Bubi. 



The Uelle district is extremely-well watered. The Uelle Biver 

 arises from the mountains situated near Lake Albert, and traverses 

 the district from east to west, throwing its network of tributaries 

 northward and southward, over a wide area representing more than 

 60,000 square miles. The southern tributaries are the most im- 

 portant; a fact easily accounted for, since the southern zone is more 

 densely wooded, and has a rainfall heavier than that prevalent in 

 the northern zone. 



A rough parallelism is noticeable in the disposition of the principal 

 affluents of the Uelle : north of the river the tributaries all run nearly 

 north-east and south-west, while those on the south side trend more 

 west-north-westward and east-south-eastward. 



Owing to the small fall of the rivers and streams the country, in 

 the rainy seasons, becomes extremely swampy : small rivers, of no 

 importance at other times, often expanding over enormous flood- 

 grounds. This is especially noticeable in the northern zone, where 

 the country is more level and the ground more argillaceous. 

 The Uelle, in common with most of its tributaries, generally winds 

 its way through high banks of clayey alluvium, and runs through a 

 broad basin, much too shallow to be termed a ' valley.' The course 

 of the stream is interrupted by numerous rapids, which divide it 

 into reaches of quieter water, easily navigable for native canoes. 

 In flood-times the Uelle rises from 12 to 15 feet, and its volume of 

 water is increased at least fivefold. 



That the pitch of the river is not great is instanced between 

 Suronga and Nfangara, the difference of level being 42*6 feet for a 

 distance of a little over 62 miles, with only two insignificant rapids. 



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