Page:Africa by Élisée Reclus, Volume 4.djvu/378

804 SOUTH AND EAST AFRICA. Physical Features. The Rufiji ( Ru-Fiji ), Rufu (Ru-Fu), and Wami Rivers, which water the region of coastlunds till recently known by the general name of the Zanzibar coast, from the neigl)l)<)uring island of Zanzibar, are characterised by basins whose natural limits are in man V places somewhat undecided. On the south west the lofty chain of the Livingstone Mountains separates the farthest sources of the Rufiji from the torrents rushing impetuously down to Lake Nyassa. This watershed is continued north- wards bv other ranges, the Yomatema heights and plateaux, all of which fall continually in this direction. Hence in the Ugogo territory crossed by the caravan routes, the transition is very gradual between the headstrcams of the Malagazi, flowing to the Congo basin, and those running east to the Indian Ocean. Here the divide is formed by an extensive tableland standing at a mean altitude of from 3,500 to 4,000 feet, and in the most elevated parts rising to 4,300 feet. Here and there the uniform surface is broken by a few granite crests cropping out through the pre- vailinir sandstone and reddish laterite formations. Northwards the horizon is limited bv the table mountains which are inhabited by the Wahuma people, and which from a distance appear to rise a few hundred yards above the level of the plateaux. The mountain ranges, properly so called, are developed entirely within the basins of the riveis flowing seawards, between the dividing tablelands and the seaboard. To these ranges liurton has given the name of the "African Ghats," comparing their outlines to those of the Indian Ghats which form the outer escarpments of the Deccan. But unlike the Indian Ghats, these LTsagara ranges are not merely the outer Cfcarpment of an elevated plateau, but, although to a less degree, present also the aspect of true mountains on their inner or landward slopes, rising on this side in steep scarps above the tableland on which they stand. Connected with the Livingstone range by a slightly inclined plateau, which is carved into terraces by the Rufiji headstreams, and which rises in some of its crests to altitudes of nearly 6,600 feet, the L'^Fagara system ramifies into two parallel main chains running south-west and north-east, in the same direction as the seaboard north of Zanzibar. Nevertheless these chains present great irregularities in their general outlines. In nnny places they throw off transverse spurs, and amid the chaos of crests every- where bounding the horizon it is often im^wssible to follow the main axis of the system. The Rubeho hills, which here form the waterparting between the Rufiji and the "W'ami basins, present on the whole the aspect of a ridge disposed in the direction from north-west to south-east. In the southern or Rufiji basin occur some coalfields, whose economic value has been differently estimated by explorers. The Usagara (L'-Sagara) Mountains are mainly of granite formation, interspersed however with diorites and other eruptive rocks, as well as with schists and sand- stones. The highest crests exceed 6,000 feet, and the Rubeho Pass, crossed by Burton and Speke in 1858, would appear to stand at an elevation of 5,700 feet. These pioneers gave it the name of the " Terrible Pass," owing to the rugged character of the escarpments and the wild disorder of the boidders which, e;chausted