THE CAPE SYSTEM 137 



left at or near the surface on evaporation of the water. 

 Hitherto such deposits, calcareous tufa, gypsum and salt, 

 have not been observed in the Table Mountain series, 

 nor have the rocks red and yellow colours, due to com- 

 plete oxidation of the iron compounds and characteristic 

 of desert sands. Perhaps the most likely explanation of 

 the deposits is that they were formed by rivers flowing 

 over a sinking area and carrying the fine-grained silt and 

 the soluble matter beyond the area in which the rocks 

 are now exposed to view. The thin layers of pebbles, 

 the isolated pebbles scattered through a sandstone mat- 

 rix, the frequent false-bedding, and the predominance of 

 sandstone are in agreement with this view. The thick 

 band of shale about 1,000 feet from the top of the series 

 probably indicates the formation of a wide lake by sub- 

 sidence, and in this lake glaciated stones were dropped 

 by floating ice. So far as we know at present there are 

 no traces of a rock or gravel floor over which solid ice 

 moved, but glacial conditions prevailed over some part 

 of the land surrounding the area of deposition. The 

 strata above the shale band are sandstones precisely like 

 those below it, and were doubtless formed under similar 

 conditions. 



The Table Mountain series yields a poor, sandy soil, 

 which in spots continually kept damp is black, owing to 

 the presence of organic matter. Vegetation is abundant 

 where the rainfall is heavy ; a heavier rainfall is re- 

 corded on or near the mountains of the south and west 

 than on the low ground on the coast side or on the in- 

 land flank. The most characteristic plants seen on 

 this formation belong to the orders Proteacea, Ericacea 



