48 THE IBIQUAS SERIES 



the rocks developed a shear structure in the sediments. 

 The grits are always felspathic and contain little pebbles 

 of quartz and sometimes of slate and phyllite. 



Similar beds are found between French Hoek and 

 Klapmuts and also on Klapmuts Hill, but they have not 

 been separated from the Malmesbury beds in the course 

 of mapping. 



THE IBIQUAS 



In the west of Calvinia and the north-eastern part of 

 Van Ehyn's Dorp there is a group of conglomerates, 

 grits, sandstones, shales and slates covered unconform- 

 ably by the Table Mountain series of the Bokkeveld 

 Mountain on the east and, in places, by the Nieuwerust 

 series on the west ; on the south-western side they are 

 in contact with the Malmesbury beds. In the east the 

 beds have low dips, but towards the west they become 

 more and more disturbed ; there is very little, if any, 

 difference between the slates of the Malmesbury and 

 those of the Ibiquas series in the greatly disturbed area 

 where the dips are often westwards at high angles, so 

 there is often a difficulty in laying down the limit be- 

 tween the two series in the absence, or lack of outcrops, 

 of the conglomerates at or near the base of the Ibi- 

 quas group. These conglomerates contain pebbles and 

 boulders of limestones, phyllites and other rocks evidently 

 derived from the Malmesbury series as well as of granite, 

 gneiss and quartz-porphyry, so they prove the later age 

 of the series and afford a good horizon for mapping 

 purposes, but the boundary runs through an area where 



1 G. C., v., p. 25, etc. ; viii. p. 149 ; ix. p. 32. 



