246 GEOLOGY OF THE ATLAS MOUNTAINS.' 



3. The Desert region^ which is the flat, comparatively 

 low tract of generally desert country, of which the principal 

 portion is the Great Desert of Sahara, which lies between 

 the 29th and 16th parallels, or about 780 miles in breadth, 

 and extending across the continent from the Atlantic to 

 the borders of Nubia. 



4. The Region of Soudan, Nigritia, or the Country of the 

 iNegroes, extending in a belt across the continent as far as 

 Abyssinia, and from the 16th to the 5th parallel, or about 

 600 miles in breadth. It is a rich and fertile region, yield- 

 ing, with little labour, all the valuable productions of the 

 tropical countries. 



5. Great Table-land of Africa, or High Africa. — This, 

 in all probability, very interesting part of Africa extends 

 from the zone of Nigritia to the Cape of Good Hope. It 

 appears to contain a lofty and extensive table-land, from 

 which acclivities, supporting ranges of mountains, decline 

 on the east and south towards the Indian Ocean ; on the 

 west to the Atlantic ; and on the north to the Country of 

 Soudan or Nigritia. Unfortunately the whole of this great 

 region, with exception of the Cape of Good Hope and 

 the Portuguese settlements on the east and west coasts, be- 

 tween which they are said to keep up a communication, is 

 unknown to us ; so that there still remains a tract of coun- 

 try, at the least 30 degrees of latitude by 25 of longitude, 

 or about 2,600,000 square geographical miles, of which 

 nothing whatever is known. Now that the thirst for 

 Arctic discovery has been quenched, and the public feeling 

 has set strongly against expeditions to Central Africa, we 

 trust that our government will be the first to engage in the 

 exploration of the great table-land of Southern Africa. 



Having premised this short account of the general fea- 

 tures of Africa, we shall now state what is known of its 

 geolosry and mineralogy, following in our account the great 

 natural divisions already pointed out. 



1. Geology of the Atlas, or Northern Region of Africa.* — 

 The northern division of Africa is principally characterized 

 by the Atlas chain of mountain-ranges, on some of the 

 loftiest points of which there is perpetual snow, which gives 

 them a height of 12,000 to 13,000 feet above the level of 



• The Egyptian, Abyssinian, and bordering African districts will be 

 considered in one of the succeeding vulumos of this work. 



