4G() MR. W. H. PENNING ON THE 



and these generally contain nuggets of gold ; but both their mass 

 and their auriferous value are very small in proportion to the rocks 

 which have been removed. The point, however, is this : admitting 

 the power of the streams to have carried away the sand and clay 

 resulting from ordinary disintegration of these rocks, the gold must 

 have remained behind with the heavier minerals that cannot be 

 transported far by ordinary agencies. Yet the absence of alluvial 

 gold is remarkable, and leads to the conclusion that the denudation 

 of the period in question was not due to rain and rivers. Equally 

 difficult is it to believe that it could have been marine ; and, at 

 first, it may seem still more difficult to account for the absence of 

 gold-bearing alluvia, as I now suggest, by the action of ice, in a 

 region lying between the 25th and 27th parallels of south latitude. 



X^revious observers have mentioned traces of glacial action in 

 South Africa, and Mr. E. J. Dunn has described and mapped the 

 Dwyka conglomerate as glacial ; but, although always on the look-out 

 for them, I have seen such traces only in two instances. It has 

 even been asserted that the whole of the western slope of the 

 Drakensberg shows signs of glaciation. This is certainly not correct 

 so far as the Transvaal is concerned, whatever may be the case 

 farther south along the extension of that range in the Free State and 

 the Cape Colony. What traces there may once have been on the 

 mountains have long since disappeared ; and, as I am now inclined 

 to believe, those at lower levels are covered over by the coal-forma- 

 tion deposited long after the (now assumed) glacial period of this 

 region. 



In 1881, when visiting the River-Diggings, where the first 

 diamonds were found, I made the following note : — " Roches mou- 

 tonnees, striated, in short valley running in at lower end of Winter's 

 .Rush," a point not far above the junction of the Yaal and Hartz 

 llivers. The striae follow the direction of the little valley, due west, 

 towards the Yaal Kiver, the recent valley thus following the line of 

 the old, which here is not an uncommon occurrence. Crossing the 

 strip of land between, one comes to another small valley, tributary 

 to the Hartz River ; here also were seen striae running north and 

 south, and thus again coinciding with the direction of the valley. 

 I have another note of an ice-marked boulder (?) near the Modder 

 River, some thirty miles S. of Kimberley, and there are " boulder- 

 clays" (glacial?) near Pietermaritzburg in iS'atal. It may be 

 admitted that these few observations of glacial markings, 300 miles 

 or more from the locality in question, form a very small basis on 

 which to found a theory of a glacial period in the Transvaal ; but it 

 must be remembered that those made near the Yaal River are at 

 2000 feet less elevation. The basis may be insufficient, but the 

 hypothesis will go a long way towards explaining some minor 

 difficulties (e. g. the formation of " pans," thus = " rock-basins ") 

 that seem to me otherwise insoluble, as well as the almost total 

 absence of auriferous alluvium in regions containing rich gold- 

 bearing deposits that have been reduced to an enormous extent by 

 erosion — glacial, fluviatile, or marine. Therefore, I am convinced 



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