"Vol. 67.] WORCESTER, ROBERTSON, JlND ASHTON (CAPE COLONY). 729 



rocks. These were undergoing rapid denudation, and the denuded 

 material accumulated at the foot of their steep southern slope, most 

 probably in disconnected basins, corresponding more or less to the 

 present distribution of the conglomerate, but of larger size. 



In order to gain some idea of the height above the present level 

 at which this denudation and accumulation took place, we must take 

 into account the thickness of the Cape System. According to the 

 best authorities, the Table Mountain Sandstone is about 5000 feet 

 thick, the Bokkeveld Series 2500 feet, and the Witteberg Series 

 also 2500 feet. On the assumption that only Witteberg Beds were 

 exposed, the ground-surface must then have been some 7000 or 

 8000 feet higher than at present. This height need not necessarily 

 have been absolute height above sea-level, but may be referred to 

 some arbitrary datum-line — for example the base of the Cape 

 System, which may then have been absolutely either higher or lower 

 than at present. 



According to this view, then, the Enon Conglomerate resulted 

 from the denudation of a land-surface, possibly a mountain-range, 

 formed of Witteberg and Karroo rocks, while the underlying pre- 

 Cambrian rocks were not exposed. There is some evidence that 

 Dwyka Conglomerate is more abundant in the lower part of the 

 conglomerate, and Witteberg Beds in the upper part, thus indicating 

 a progressive uncovering of lower and lower beds ; but on this point 

 much more work is needed before it can be regarded as established. 

 Then, after the formation of the Enon Conglomerate, the major 

 portion at any rate of the fault-movement took place, bringing Enon 

 Conglomerate in places into juxtaposition with Malmesbury rocks. 

 This fixes the age of the fault as post-Cretaceous. 



The disposition of the minor lines of folding in the region to the 

 south of the fault is in favour of the view that a close connexion 

 exists between the folding and the faulting. North of the fault 

 the strike of the Cape rocks of the Langebergen is uniformly east 

 and west, and the dip is steeply northwards. South of the fault, 

 however, they are ridged up into a series of sharp anticlines and 

 synclines, with axes running approximately north-north-east and 

 south-south-west, and occasionally accompanied by parallel faults : 

 as, for example, west of Lady Grey. The trend-lines of these 

 structures are, therefore, nearly at right angles to the principal fault. 

 It appears, then, that when the region to the south of the fault sank 

 down, it also underwent a sort of lateral crumpling due to com- 

 pression. 



Let us now turn to a consideration of the events which succeeded 

 the formation of the Enon Conglomerate. As we have already seen, 

 the evidence suggests that the conglomerate was formed on an old 

 land-surface, composed of Ecca, Witteberg, and Bokkeveld rocks. 

 Then, as a result of earth-movement, or possibly on account of a 

 release of pressure, subsidence took place along a fault-line (which 

 had probably been already initiated), resulting in the formation 

 of the great Worcester-Swellendam Fault. This fault must be 



