The prevailing geological formations are the crystalline rocks, such as granites, diorites, slates, gneiss, underlying the old and new alluvia of the plains, and found associated with sandstones in the highlands. In the Kong Mountains the granites underlie the sandstones, but in the Tagalé group (South Kordofan) they pass over to porphyries and syenites, interspersed with extensive diorites and auriferous quartz veins. Volcanic rocks (basalts, lavas, tufas) appear to be restricted to the isolated Defafaung and Alantika Mountains (Adamawa) although solfataras occur in the Tagalé district where sulphur abounds. Mineral waters are also found in Dar-Fur and Adamawa.

The most widely diffused minerals are iron and copper, the oxides of iron occurring almost everywhere from the White Nile to the Niger, while pure copper is met especially in Dar-Fur and Fertit. Gold is chiefly restricted to the Tagalé and Kong Mountains. Barabarra, and Adamawa; and lead, antimony, and tin are confined to a few isolated districts. Characteristic is the apparently total absence of limestones, coal, salt, and natron, the supplies of salt being imported mainly from the Sahara. Report, however, speaks of a large lake in the Jebel Marrah, from which salt is obtained. [22.291]

Related material


“Soudan.” The Encylopædia Britanica or Dictionary of Arts, Sciences, and General Literature. 9th ed. Philadelphia: Maxwell Sommervile: 1894. 25 vols. Hathi Trust Digital Library online version of a copy in the University of New York Public Library. Web. 20 August 2020.

Last modified 20 August 2020