PRE-CAPE ROCKS OF THE NORTH OF THE COLONY 63 



dently the equivalents of the diabases and diabasic tuffs 

 seen to the north-west. The rocks have been much 

 fractured and veined by quartz, the veins being of dif- 

 ferent ages. The older quartz veins have been contorted 

 and granulitised by subsequent earth-movement. Gold 

 has been found in several of these veins, notably at 

 Madibi and on Wodehouse Kraal. In the former 

 locality the vein stuff consists of quartz, chlorite, pyrites 

 and pyrrhotine. and it fills a fissure traversing the 

 chloritic schist. The auriferous reefs at Abelskop and 

 Goudplaats in the South- Western Transvaal appear to 

 traverse rocks belonging to the Kraaipan formation also. 



Small patches of a magnetic quartzite are seen north 

 and north-west of Vryburg, while a large band of mag- 

 netic quartzites, slates and interbedded quartz-porphyries 

 strikes east and west a little north of Takoon. 



The question of the relationship of the Kraaipan 

 formation to the Kheis series has been discussed on a 

 previous page. 



3. THE WILGENHOUT DRIFT SERIES. 1 



Near Wilgenhout Drift on the Orange Biver above 

 Upington there is a group of rocks not yet correlated 

 with any other formation. The series consists of sheared 

 diabase lavas, tuffs, quartzites, slates, crystalline lime- 

 stones, quartz-porphyries, and a few bands of conglo- 

 merate with quartz-schist pebbles in them ; possibly 

 also some ferruginous cherts are part of the series. 



These rocks have been examined in a strip of 

 country ten miles long on the right bank of the river, 



J G. C., xii.,pp. 35-42. 



