ORIGIN OF RAND BANKETS. 53 



bedded and occasionally showing bands of white quartz-pebbles, 

 sometimes even odd boulders of considerable size. Towards 

 the top there is a wide shale-band, which in the north-west 

 contains glaciated boulders. The whole aspect of the series, 

 which at its fullest is 5,000 feet thick, is that of a deposit laid 

 down close in-shore, with turbulent and shifting currents. It has 

 been proposed, to account for the false-bedding, that it is a 

 sub-aerial deposit, as Tennison Woods proposed for the Austra- 

 lian Hawkesbury sandstones, which, in many respects, are 

 similar to the Table Mountain sandstone, but the shale-band 

 within the Table Mountain Series and the perfectly conform- 

 able junction with the Bokkeveld marine beds above negative 

 this conclusion; while the sand-grains are of the ordinary water- 

 worn variety, and are not rounded by wind action. There was 

 a southern land-surface which, however, only comes into actual 

 observation in the succeeding Karroo period ; it is usually regarded 

 as a long narrow peninsula like the Malay Peninsula, and, as 

 Madagascar is a remnant of this land-surface, it is conveniently 

 referred to as " the old [Madagascar ridge." Whether the expla- 

 nation of the false-bedding in the Table Mountain sandstone 

 can be helped by this ridge is a matter of opinion ; the turbu- 

 lence of the water flowing backwards and forwards through a 

 comparatively narrow strait would produce the intense false- 

 bedding. Until, however, the old Madagascar ridge rose still 

 further and formed the southern boundary of the great Karroo 

 lake we have no definite knowledge of its existence, hence any 

 explanation that implies its presence in previous times must be 

 merely speculative. 



The northern shore of the Table Mountain sea then retreated 

 northwards, and over the shore deposits of that period were 

 laid down the deep-water deposits of the lower Devonian. We 

 are certain that these sediments were derived from a land-surface 

 to the north, because in the width of the exposure on the south 

 coast the beds on the north are interstratified with three great 

 bands of white quartzite, showing that the sea-floor was oscillat- 

 ing, and that every now and again it came within the reach of 

 littoral deposits; on the south, near the present coast, however, 

 these sandstone bands are only feebly developed, or are entirely 

 absent, indicating deeper water conditions. Where the now sub- 

 merged coastal plains existed in the period of deposition of the 

 Table Mountain sandstone, the littoral deposits of the Bokkeveld 

 beds w^ere laid down ; these consisted probably of sediments 

 dififering but little from those of the Table Mountain sandstone. 

 In the following period, the Witteberg, the shore-line again 

 crept southwards till it reached — 'Or probably surpassed by a 

 little — the line it occupied in Table Mountain times : the loose, 

 recently formed Bookeveld littoral deposits were exposed to 

 the action of denudation, and became washed down by the rivers 

 and laid upon the deep-water sediments of the Bokkeveld. Hence 

 the sand-grains would suffer a double attrition, first after their 

 original disintegration from the rocks, granite, etc., of the old 



