216 THE GEOLOGY OF THE ZAMBEZI BASIN. [May I907, 



'pipe-amygdaloid/ It was interesting to note that the Author 

 also referred to the occurrence of a ' pipe-amygdaloid ' in the 

 Batoka Basalts. The Yolcanic Group of the Drakensberg was 

 classified by South African geologists, following Dunn, as the 

 uppermost division of the Stormberg Beds, and consequently as 

 younger than the Permo-Carboniferous coal-beds of Cape Colony. 



Considering the vast extent of the plateau-basalts of North 

 America and of the Deccan in India, geologists would admit the 

 possibility that in South Africa these great basaltic flows of 

 Rhodesia, the Transvaal, and the Cape Colony may have had 

 a common genetic origin, and were erupted towards the close of the 

 Stormberg Period. 



There appear to have been three chief epochs in the geological 

 history of South Africa, when volcanic activity took the form of a 

 vast extrusion of lava. The first followed the close of the 

 Witwatersrand Period, producing the lavas, accompanied by 

 breccias and tuffs, of the Yentersdorp Volcanic System. The 

 second followed the deposition of the Pretoria Beds, producing 

 the acid felsites of the so-called ' red granite '-formation of the 

 Transvaal; while the third took place towards the close of the 

 Karroo Period, producing the basic lavas of the Stormberg, the 

 Springbok Plats, and (as it would appear) the Batoka Basalts. 



The Author expressed, in reply, his thanks for the reception 

 accorded to his paper. 



