428 THE TABLE MOUNTAIN SANDSTONE 



rocks which now rest on the folded beds belong to the 

 base of the Karroo system and are unaffected by the 

 folds. That this immense gap in the northern succes- 

 sion is partly represented in the south of the Colony by 

 the Cape system (Lower Devonian to Carboniferous) 

 admits of little doubt, but one of the great problems in 

 South African geology is to find how much more of the 

 Palaeozoic, and perhaps Pre^Palaeozoic, strata are miss- 

 ing in the north. 



At the commencement of the Cape period, i.e., about 

 Lower Devonian times, w r e may imagine that a great 

 tract of land lay west and north of the position of the 

 southern part of the Colony, for the materials comprising 

 the Table Mountain series become somewhat coarser in 

 those directions. That land furnished the enormous 

 amount of sand, almost entirely of quartz grains, that 

 now is the Table Mountain sandstone. This sandstone, 

 which is roughly in the form of a broad belt about 500 

 miles long and 100 wide, was deposited in shallow 

 water; denudation and earth-movements have played 

 a greater part in defining its present boundaries than 

 original deposition. During its formation the floor 

 must have been gradually sinking to allow of the 

 accumulation of 5,000 feet of sediment which through- 

 out bears evidence of deposition in shallow water. The 

 shale bands may possibly indicate deeper water con- 

 ditions, but not necessarily so ; the striated boulders in 

 the Pakhuis shales and mudstone and in the sandstone 

 of Table Mountain prove that glacial conditions pre- 

 vailed for a time during that remote period. The fact 

 that the series is thinner near Nieuwoudtville, at the 



