Note on the Rocks of Darfur. 207 
The figure of the latter rock in Harker’s Petrology for Students, 
1919 (fig. 24, p. 80) affords a good representation of the Khor el 
Haggis rock. 
The granite of Dilling has been described by Linck.* Specimens 
(45) collected by Lynes show the proportion of potash-felspar 
(microcline and microperthite) to oligoclase to be 2:1. Linck 
describes numerous dark inclusions in the granite of Kadero, to the 
east, and they are evidently abundant in the granite of Dilling too. 
Those collected (46) are fine-grained (0°08 mm.), equigranular 
aggregates of biotite and felspar (? orthoclase), quartz, and ilmenite 
(or magnetite), with abundant round grains of sphene, and fine 
needles of apatite crowding the felspar hosts. These inclusions 
carry some large crystals of plagioclase full of inclusions. The 
plagioclase is albite-oligoclase. One crystal showed a more acid 
centre, with inclusions of blebby quartz. 
Scale of Miles. 
° 60 100 200 
Figure 4 
Fragments of very weathered granite (44) found on a hill near 
Ullul seem the most westerly representative of the Nuba Mount 
granites, but at 30 feet, in a well-boring at Abu Zabbad, occurs a 
pure white pegmatite or graphic granite (43). It consists of 
orthoclase, albite-oligoclase, and quartz, the two last often 
eraphically intergrown, in plates of about 1 cm. in average diameter, 
with occasional plates of biotite altering to chlorite. Zircon was the 
only accessory mineral observed. 
On the direct route from El Obeid to El Fasher the ground is at 
first covered with the hard red sand, like that which is so widespread 
in Kordofan. To the south the Nuba Mountains are seen in the 
distance, but near the route a very occasional little kopje or rocky 
outcrop is all that is seen to break the level plain. 
At Jebel Waled, 6 miles east of Nahud, sedimentary rocks appear. 
They are similar to those forming the Lugud Hills, which are 
described below. A well-boring at Nahud is in pale yellow friable 
sandstone, containing pebbles of chalcedony (40). 
1 Loe. cit., p. 407. 
