THE GEOLOGICAL HISTORY OF THE COLONY 443 



to indicate that the region of the Great Karroo acted as 

 a block against which the strata of the folded belt were 

 crumpled and turned over. The over-thrust faults in 

 the Dwyka series near Laingsburg also dip to the 

 south, as though the pressure had to be relieved by the 

 sliding of blocks of beds over the fractured edges of the 

 next block to the north. It is on the south flanks of 

 the most crumpled ranges that the great strike faults of 

 Worcester and the Cango occur, and their downthrows 

 are very considerable, reaching at least 10,000 feet at 

 Worcester. The western folds are not nearly so in- 

 tense as the southern, and may have begun at an 

 earlier date. The easternmost of these anticlines, that 

 which forms the Cederbergen, is also the greatest, and 

 it is fairly symmetrical ; no considerable folds lie paral- 

 lel to it on the east; to the west, however, there are 

 several parallel folds decreasing rapidly in amplitude 

 towards the coast. 



The neighbourhood of Worcester, where the Uiten- 

 hage conglomerates lie upon the Ecca beds and the 

 Pre-Cape rocks on either side of the great fault, affords 

 a grand object-lesson in denudation. To the north of 

 the fault 4he conglomerates lie directly upon the Mal- 

 mesbury beds ; to the south, part of the Ecca, the 

 Dwyka series and the whole of the Cape formation in- 

 tervene between the two. The thickness of the inter- 

 vening rock is not less than 10,000 feet. Between the 

 fault and the mountains to the north of it over 10,000 

 feet of rock must have been removed during the interval 

 (Jura-Trias) spoken of above. Nowhere else in the 

 Colony is the evidence of this denudation so clear as at 



