70 THE ZOETLIEF SERIES 



ley mine some 300 feet of sedimentary rocks, including 

 conglomerates with pebbles of granitic rocks, quartzites, 

 and quartz, lie below the quartz porphyries, but at the 

 De Beers mine the latter rest directly on the granite. 

 Farther south, on the Kiet River west of Modder 

 River Station, amongst the volcanic rocks of the Pniel 

 series inliers of the acid lavas occur, while two more 

 project through the Dwyka near Klokfontein Siding. 

 Between Strydenburg and Omdraai's Vlei there are in- 

 liers surrounded by Dwyka tillite at Wonderdraai and 

 at several places near Beer Vlei ; in the T'Kuip hills 

 300 feet of arkose, conglomerates and breccias lie on 

 the granite, but they are overlapped towards the south 

 by some 500 feet of the overlying acid lavas, which are 

 in turn covered unconformably by the Kuip series. A 

 small hillock of the quartz-porphyries rises from the 

 granite on Maritz Dam ; the rock is banded, and the 

 bands are due to movement in the lava when it was 

 liquid ; they dip inwards towards the longer axis of the 

 hillock, which probably marks the site of a volcanic 

 neck. 



Acid porphyries lying in the very much sheared belt 

 between Uitspansberg and Geelbeck's Dam in Prieska 

 may belong to the Zoetlief series. 



B. THE KUIP SEEiEs. 1 



In the T'Kuip hills near Omdraai's Vlei a group of 



some 1,500 feet of diabase lavas and sedimentary rocks 



lies between the Zoetlief beds and the Pniels, with an 



unconformity both above and below. The lavas rest 



1 G. C., xii., p. 168. 



