Vol. 67.] WORCESTER, ROBERTSON, AND ASHTON (CAPR COLONY). 715 



grapher, another interesting feature is that, broadly speaking, the 

 anticlines form hills and the synclines valleys, contrary to what is 

 usual in folded regions. The Breede River cuts through an anti- 

 clinal hill about 4 miles west of Robertson, and in the gorge thus 

 produced some magnificent examples of folding on a large scale may 

 be observed both from the road and from the railway. In general 

 terms, it may be said that throughout this district the most elevated 

 ground consists of Table Mountain Sandstone and Witteberg 

 Qnartzites, whereas the Bokkeveld Beds, being softer, form low 

 ground, and are often completely hidden by alluvium. 



(1) The Malmesbury Rocks. 



The rocks composing the Malmesbury Series in the district near 

 Robertson are very similar in general character to those of 

 Worcester ; hence it is hardly necessary to describe their lithological 

 character in detail. They consist of a fairly uniform series of rather 

 fine grits and slates of a grey, greenish, or silvery colour when 

 fresh ; but, when much weathered, as is commonly the case, the 

 prevailing tint is a pale olive-brown. A bed of dolomite is seen at 

 Keur Kloof, about a mile north of Robertson, and another outcrop 

 of what is (in all probability) the same bed occurs in the road which 

 runs up the valley of the Hoops River, about 3 miles to the east. 



The outcrop of the Malmesbury rocks is here rather narrow, 

 averaging not more than a mile in width, except in the neigh- 

 bourhood of the granite mass, where it expands greatly, as seen 

 on the map. There are not sufficient data available to show to 

 which division of the series, as defined at Worcester, they should be 

 assigned. 



In the neighbourhood of the granitic intrusion of Wolve Kloof 

 the Malmesbury rocks are highly disturbed, but there is little or no 

 evidence of thermal metamorphism, although the actual contact of 

 the granite and sediments is exposed in several places. Along the 

 footpath which runs from Robertson to Wolve Kloof, near the 

 ruined water-mill at the entrance to the Kloof, there is a rapid 

 alternation of granite and apparently unaltered sediment, each of 

 which occurs along the path in patches a few yards wide. The 

 junction is evidently very irregular, with tongues of granite pro- 

 jecting into the slates. The, latter are much sheared, but no 

 development of contact-minerals can be seen. A short distance 

 north-east of this point, at the top of the first cultivated field on 

 the side of the hill, is an exposure of rock of the phyllite-gneiss 

 type, evidently a crushed granite-dyke. 



The succession of the Malmesbury rocks is seen most completely 

 along the road which leads up the valley of the Hoops River. From 

 Robertson as far as the river this road runs over Witteberg Slates 

 and Euon Conglomerate, both of which are well exposed in several 

 cuttings. Near the drift over the river, about 2 miles east of 

 Robertson, there are not many exposures ; but a few yards beyond 

 the drift there is by the roadside a patch of typical Malmesbury 



Q.J. G. S. No. 268, 3 c 



