ORIGIN OF KA.\D 1!.\ NKKTS. 57'. 



froni the same range of mountains, whicli. in the process of 

 time, have been worn down so that the deeper lying beds have 

 been exposed. These deeper rocks — the Table [Mountain sand- 

 stone, for instance — do contain small reefs of gold in quartz 

 veins and bankets, and the gravels derived from them, there- 

 fore, are auriferous, as on the Poverty Flats in Knysna. 



The Systk.m of Folds on the South Coast. 



To confine the limits of this paper, we can restrict our at- 

 tention to the folds which run almost due east and west along 

 the western margin of the south coast of South Africa. The 

 area of the earth's crust has sustained a thrust from the north,, 

 due to the intrustion of dolerite in the Central Karroo and 

 accompanying disturbances, which has been brought up against 

 a line of granite bosses, which have barred the way for the 

 movement of the earth's crust seawards. The result of the 

 thrust is 'best seen on the road from Mossel Bay to Oudtshoorn 

 and Prince Albert : the Table Mountain sandstone has been folded 

 like a sheet of paper into innumerable folds, closely pressed 

 together (isoclinals) to the south and more open to the north,, 

 but most of the limbs inclining seawards. To the east of George, 

 where the granite ends, the strike of the folds splays out sea- 

 wards and the ranges run east-south-east. It has frequently 

 been advanced that the granite bosses pressed in from the sea; 

 but if a series of folds are compressed at the base, they must 

 incline in the direction of the thrust, hence the thrust, to my 

 mind, must have come from the north. The dolerite intrusions 

 of the Central Karroo are contemporaneous with the folding, 

 and are an adequate cause. In the Alps a further action has 

 taken place: the thrust from the north, spending itself on the 

 line of granite bosses in the north of Italy and adjoining countries 

 to the east and west, has caused the beds caught in the nip to 

 crumple up with the axes of the folds fan-fashion ; in the Soutit 

 African coastal ranges the north side only of the Alpine struc- 

 ture is developed. There are beds of Banket in the Table Moun- 

 tain sandstone, but they are only recorded from Knysna and 

 Oudtshoorn in single occurrences ; had the banket been more 

 prominent, and had it been exhibited in, say, the section of 

 mountains between Alossel Bay to Oudtshoorn called the Outeni- 

 qua Mountains, then the banket would have appeared at the 

 surface some six or eight times, each bed apparently above the 

 other and to all appearances conformably above the last. Such 

 a false conformity has been called by Grabau a disconformity. 

 Had, further, the banket been like the Enon Conglomerate, which, 

 as it is followed from- place to place, changes from a series of 

 continuous gravels to a more or less alternating series of sands 

 and gravels, each banket reef would appear to be diiiferent from 

 the ones above and beloiw, although we could, in the case of 

 the Outeniqua Alountains. prove that the banket was continuous 

 up ap.'l flown the loops of the closely compressed synclines and 

 anticlines. 



