THE GEOLOGICAL HISTORY OF THE COLONY 429 



extreme northern end of the area occupied by the over- 

 lying Bokkeveld beds, than farther south, points to the 

 subsidence which allowed of the accumulation of the 

 sandstones having gradually proceeded northwards. 

 This means that deposition began in the south earlier 

 than in the north, so that the bottom of the series in the 

 Bokkeveld Mountain area was formed later than the 

 lowest beds in the Worcester or Ceres Divisions. 



We cannot regard the Table Mountain series as a 

 marine formation ; it is probably a fluviatile deposit 

 laid down near the source of origin of the materials 

 composing it. The great thickness of sediment, and 

 the evidence throughout that it was laid down in shallow 

 water, prove that the area occupied by it underwent 

 slow but steady depression, which continued for a long 

 period after the peculiar conditions under which it was 

 formed came to an end. This depression in the southern 

 part of the Colony must have gone on till some time 

 during the deposition of the Karroo formation, perhaps 

 till late in the Beaufort period ; it was brought to a close 

 by the earth-movements which produced the southern 

 and western mountain ranges. 



The northern limit of the depressed area cannot be 

 defined, but it probably lay to the north of the thirtieth 

 parallel ; beyond the Orange Kiver there was probably 

 land. 



During the Bokkeveld period the waters of a southern 

 ocean that lay south and west of the Colony, and which 

 spread at least as far as the position of the Falkland 

 Islands and the South American Continent, gained 

 access to the area where the Table Mountain series 



