ECONOMIC GEOLOGY 463 



the Malmesbury series furnish, when decomposed, a 

 clay that can be utilised for such a purpose, while red 

 clays belonging to the Uitenhage formation are worked 

 near Kawson Bridge, Despatch and Uitenhage. The 

 blue-grey clays of the Uitenhage series at Heidelberg 

 are made into good tiles, pipes, and bricks. Thick de- 

 posits of clay have been found in a few localities under- 

 lying the sand and gravel of the Cape flats ; they include' 

 china clays of excellent quality. Beds of fire-clay are 

 associated with some of the coal seams of the Molteno 

 beds, and at Cyfergat a seam is being mined for the 

 manufacture of bricks. Thick beds of fire-clay have 

 been proved overlying a seam of coal just north of 

 Sterkstroom and underlying the coal of the Guba Valley, 

 near Indwe. 



Coal. As already stated in describing the "White 

 Band " of the Dwyka series, much prospecting for coal 

 has been done in this zone of carbonaceous shale with- 

 out any encouraging results, neither has any evidence 

 yet come to light in support of Dunn's view as to the 

 probable existence of workable coal a little above the 

 Dwyka conglomerate under the Karroo. 



The lowest geological horizon at which coal has been 

 found belongs to the Lower Beaufort beds, for behind 

 the Komsberg escarpment there is a seam about nine 

 inches thick on the farm Lange Kuil, while thicker 

 seams have lately been discovered in the escarpment 

 a little distance to the south-east. High up in the 

 Nieuweveld escarpment at Leeuw Kiver Poort, and .also 

 in the Camdeboo, there are some remarkable vertical 



