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Transactions of the Boyal Society of South Africa. 
Britstown for example. Although this is the case over a large area, I 
think that the proportion of country possessing stronger relief has been 
much underestimated. For example, we have the Karreebergen and the 
block of rugged ground joining the Nieuwveld to the Sneeuwbergen and 
Stormbergen. The Dwyka and Ecca shales crumble away rapidly and 
form flats dotted with little dolerite ridges and pinnacles, while the 
Beaufort sandstones are far more resistant. Again, the inclined sheets 
or sills of dolerite form far more serious obstacles to denudation than the 
nearly horizontal intrusions ; the latter, when they occur on the flats, are 
not uncommonly decomposed to a friable material. The time required for 
the dissection of the peneplain into such an area of low or moderate relief 
may therefore have been comparatively small; thus the argument that 
with a late uplift of the continent the stream- courses would be incised and 
the rivers would have been unable to cut out a peneplain is very much 
weakened. As a matter of fact, however, it is just the incised nature of 
the channels of the Orange and Vaal Elvers which has prevented the 
development of irrigation schemes along their courses, while it has 
already been pointed out that the Orange Eiver flows in a gorge through- 
out this area, the same being true of its channel below Prieska and below 
Upington. With a late uplift, however, there may have been rejuvenation 
of the lower reaches of the Orange, while the upper portion of the drainage 
system may have been but little affected by the elevation. 
The view that the " Veld " is due to erosion under arid conditions 
within recent times is not borne out by facts. Firstly, gravel terraces 
occur at various altitudes as already described ; secondly, the existence 
of dry river-channels, such as the Molopo in Bechuanaland, indicate that 
the rainfall is probably less at present. At the present day the rivers are 
quite able to dispose of the products of disintegration, for the flats are 
covered with but a scanty soil. Belts of sand cover extensive tracts of 
country, but the material is principally wind-borne, and is due to invasion 
from the north-west ; practically, however, the whole of the sand is fixed 
by grass. 
The existence of numerous pans inland affords no decisive evidence of 
climatic changes. There is no doubt that they have been formed princi- 
pally through the agency of the prevailing northerly or north-westerly 
winds," but while some pans are being filled up with sand at the present 
day others are undoubtedly being deepened. Their positions are usually 
independent of any drainage system. 
From the writings of the older travellers, which are confirmed by the 
accounts of the oldest residents in the Colony, there is no doubt that the 
human habitation of the Colony has been a most important factor, and one 
that has not been sufficiently reckoned with in modifying the face of the 
* Ann. Rept. Geol. Commn. for 1906, p. 131. 
