140 THE BOKKEVELD SERIES 



sandstone, and far to the north-east the St. John's and 

 Egossa forests are on the same formation. Elsewhere 

 the forests are mere remnants preserved in steep kloofs, 

 and they do not spread over large parts of the moun- 

 tain sides. 



2. THE BOKKEVELD SEEIES. 



The Bokkeveld series is everywhere found lying 

 directly upon the Table Mountain series, with similar 

 strike and dip, and there are no signs of unconformity 

 between the two. In some localities, such as the small 

 sandstone anticlines in the Warm Bokkeveld and the 

 anticlinal ridge of Jan Niemand's Bosch near Houwhoek, 

 water seems to have percolated freely at the junction of 

 the two formations, the position of which is marked by 

 a layer of crystalline quartz. There are few places 

 where a clean-cut section of the junction can be seen, 

 for the soft beds of the bottom of the Bokkeveld group 

 have generally been worn away by small streams, the 

 beds of which are choked up by debris from the sand- 

 stones when the strata are at all steeply inclined. 

 Where the beds lie nearly flat, as they do north of the 

 Doom River in the Western Karroo, the junction is 

 hidden under the soil. The best section hitherto found 

 is that on the left bank of the Gamka Eiver immediately 

 above its great Poort through the Zwartebergen, and 

 there "the end of the white sandstones and the be- 

 ginning of the blue-black shales of the Bokkeveld is so 

 sudden and exact that one can place a knife between 

 them and say confidently that on one side are the rocks 

 of the Table Mountain series and on the other those of 



