8 president's address. 



foot peneplain to the east, but it seems likely that the old 

 western land surface was continuous with the surface in which 

 that peneplain was being cut, though it is probable that the 

 western surface is the older of the two; that it happened to be 

 preserved at an earlier stage for our inspection. The position of 

 the Cretaceous shore in the west is not known ; neither Cretaceous 

 nor Tertiary marine beds have been found on the west coast 

 south of Buntfeldschuh, but in the absence of evidence of faults 

 of Tertiary age on the west coast one is justified in expecting 

 that Tertiary inshore deposits await discovery south of the 

 Orange River in positions analogous to those of Granitberg and 

 Buntfeldschuh. 



The most definite evidence of the climate under which was 

 developed the surface represented by the 4,600 foot peneplain 

 in the east and thei buried floor of the Henkries valley in the 

 west, comes from the latter valley, which at the time when it 

 began to be filled in had greater depth relatively to the hill 

 flanking it than it has to-day. It is obviously a stream-cut 

 valley, but when the Dinosaurs whose bones were found lived 

 there, the stream was no longer able to keep the channel open; 

 the valley became filled in with the quartz and felspar grit 

 through which the well was dug, and ever since then the process 

 of accumulation has, on the whole, continued; the climate has 

 not become sufficiently humid to supply a stream which could 

 re-excavate the valley. The bottom of this valley is still the 

 earliest known record of the post-Karroo land surface in the 

 country north of the Cape ranges. Whether the thick super- 

 ficial deposits on the eastern flank of Kamiesberg" belong to 

 the same period is not yet known, and no corresponding dis- 

 covery has been made in the Kalahari. The known position of 

 the Karroo beds in the south-west of Bushmanland and the 

 down-faulted outliers near the Orange River at Viool's Drift 

 make it very probable indeed that the Karroo beds covered the 

 Henkries valley, and the sti-eams which removed them would 

 seem to have had a greater supply of water than there is in that 

 region to-day; the diminution of rainfall, if that were the 

 immediate cause, took place in late Cretaceous or early Tertiary 

 times. Passarge tentatively attributed part of the cementation 

 by silica of the Kalahari sand to pre-Tertiary events," and that 

 such did take place then is rendered very probable by the close 

 association of sihceous concretions with the Dinosaur bones in the 

 well at Kangnas. 



A few years ago very interesting observations bearing on the 

 climate of the Namib in Tertiary times were made by Professor 

 Kaiser and Dr. Beetz, who found " a large species of Helix " 

 in the silicified rocks of the Pomona Tafelbergen, and remains 

 of vertebrates in the marly sandstones of Elizabeth Bay, and also 

 other fossils.-' These have not been described so far as I know, 

 and their discussion may be expected to give most valuable 

 information. Professor Kaiser states that they indicate the 

 terrestrial deposition of the beds concerned, and that these are 



