78 THE KORAS SERIES 



from the Kheis series, granites and lavas and porphyries 

 from the lower beds. They are often closely packed, 

 and the pebbles in contact with each other are fractured 

 and indented. 



The finer grained sedimentary rocks are felspathic 

 sandstones and quartzites of a dark red colour ; they are 

 thick bedded and remarkably free from current-bedding 

 and laminae. They must be several hundred feet thick, 

 but neither the thickness of the beds nor that of the 

 lavas has been measured. 



Though the Koras beds on the whole resemble the 

 Pniel series more than any other group there are con- 

 siderable differences between them, especially that due 

 to the red colour of the Koras beds. This character is 

 so uniformly shown by the sediments that it was prob- 

 ably an original feature. 



The beds have been placed in the Ventersdorp system, 

 but they may be of much later date, later even than the 

 Matsap series. 



The country they occupy has a very different appear- 

 ance from that of the surrounding older beds. The 

 lavas give rise to low rounded hills which contrast 

 strongly with the sharper forms assumed by the steeply 

 dipping Kheis and Wilgenhout Drift beds. 



2. THE TEANSVAAL SYSTEM. 1 



In the country north of the Karroo, where the Karroo 

 formation has been removed by denudation over wide 

 areas, a large part of the surface is occupied by the 



1 Also called the Potchefstroom (Hatch and Corstorphine), and the 

 Lydenburg (Dunn and Passarge) System. 



