548 MR. D. DRAPER ON THE GEOLOGY [NOV. 1 894, 



35. Notes on the Geology of South-eastern Africa. By David 

 Draper, Esq., F.G.S. (Head May 23rd, 1894.) 



[Plates XXII. & XXIIL] 



Contents. 



Page 



I. Introduction: Physical Features 548 



II. Geological Features 550 



III. Conclusion 556 



IV. Supplemental Notes on the Dwyka Conglomerate... 559 



I. Introduction : Physical Features. 



I purpose, in the following pages, to give a brief description of the 

 principal physical and geological features of that portion of South 

 Africa which is situated between the 26th and 31st degrees of south 

 latitude and the 29th and 31st degrees of east longitude. 



This area includes the Colony of Natal, the native States of 

 Zululand and Swaziland, the south-eastern portion of the South 

 African Republic (Transvaal), and the eastern portion of the Orange 

 Free State and of Basutoland. 



The leading physical features of this area are : — 



(1) The Drakensberg Range. 



(2) The ' Terrace,' lying along the foot of the Drakensberg. 



(3) The Coast-belt, between the Terrace and the Indian Ocean. 



(1) The Drakensberg Range. 



This range of mountains is the continuation of the main range, 

 which runs roughly parallel with the coast-line of Cape Colony, from 

 west to east, and turns rather suddenly northward at the Natal 

 boundary. It is known under various names in Cape Colony, and as 

 the ' Drakensberg ' where it forms the boundary of East Griqualand 

 and the Colony of Natal. 



The Drakensberg forms the watershed of the south-eastern 

 portion of the continent ; it divides the waters flowing westward 

 into the Atlantic from those flowing eastward into the Indian Ocean. 

 The rivers flowing westward, viz. the Orange and the Vaal, drain 

 the inland portion of South Africa. Those flowing eastward, the 

 principal of which are the Tugela, the Usuto, and the Pongolo, drain 

 the coastal portion. These latter are small in comparison with the 

 Vaal and Orange rivers. 



The Drakensberg range consists of three distinct portions, 

 differing greatly in aspect. (See PI. XXII.) 



(a) The Mountain portion, extending northward to the ' Mont- 

 aux-Sources,' forming a bold and rugged mountain-chain, 

 inaccessible except by means of a few obscure and dangerous 



