274 NOETH-EAST AFEICA. 



a circular enclosure. In the more remote regions of central Dar-For are also a 

 few isolated uplands. The confines of Wadai, towards the north-west angle of 

 Dar-For, are indicated from afar by the Jebel-Abû-Ahraz, or the " Mountain of 

 the Father of the Acacias." A second height, better known, as it commands the 

 caravan route from Kobeh to Siut to the west, develops its peaks, such as the 

 Jebel-Dor and the Jebel-Anka, in a line with the northern continuation of the 

 main axis of the Marrah range. 



To the north-east of Dar-For, the Jebel-Medob lifts its sandstone walls and 

 granite cupolas, here and there broken by lava streams, to a height of nearly 4,000 

 feet. Beyond this point extends the plateau of the Jebel-Ain, skirted by the 

 Wady-Melek. To the east the Jebel-el-Hillet, which is skirted by the route from 

 El-Fasher to El-Obeid, and to the south, in the hydrographie basin of the Bahr-el- 

 Arab, are still several other isolated uplands, connected by no intermediate ridges 

 with the Marrah highlands. The Jebel-Hadid, one of these groups of hills, is 

 very rich in iron ores. Some 30 miles to the south-west of the Jebel-Dango, 

 another mountain mass rising above a plain, are the copper-mines of Hofrah, 

 celebrated throughout the whole of central Africa. The mineral vein which is 

 now being worked lies on the right bank of the Bahr-el-Fertit, an affluent of the 

 Bahr-el-Arab. An excavation, 500 feet long by 50 feet broad, with a mean depth 

 of 10 feet, has been dug out by the miners, and shafts, now abandoned, have been 

 sunk in all directions within a radius of 1,660 feet from the pit. It was mainly 

 with a view to obtain these copper-mines that the Khedive caused Dar-For to be 

 occupied. Few other regions have been the cause of more wars between the 

 African populations than these now valueless mineral beds. 



Hydrographic System. 



The rainfall and the waters of the wadies are regulated by the atmospheric 

 currents, as in Kordof an ; however, it would appear that the higher mean elevation 

 and the greater extent of the Dar-For highlands cause more of the rain-bearing 

 winds to be arrested, thus securing a more copious rainfall for this region. 



Near the centre of this mountainous district, in a closed amphitheatre, lies a 

 lake which has never yet been visited by European travellers. 



The rains are more abundant in the western region of Dar-For ; and as the 

 concave side of the crescent- shaped Marrah range faces westwards, the water- 

 courses of this watershed all converge on the main branch, the Wady-Azum, a 

 relatively copious stream, although its bed is dry for a portion of the year. On 

 the convex slope of the Marrah Mountains the running waters, diverging east and 

 southwards, become lost in the desert, and hence are unable to unite their sandy 

 beds in one common hydrographic system. On the southern slope alone, where 

 the rains fall more frequently, the rivers have a longer course and constitute 

 veritable fluvial basins. Thus, during the rainy season, the Wady-Amor and the 

 "VVady-el-K6 combine to fill a rahad or lake of some considerable size, at which the 

 Rizegat Baggâras water their cattle. 



