Bee see ES CLAW LAIR, 
tract of country which has been cleared of its covering of glacial drift 
and stands today with many of the features which it presented in a 
remote geological period. The glacial drift is of Permian age, and 
the topography revealed with astonishing freshness, belongs to that 
or earlier epochs. The area was described by Dr. Rogers and myself 
in 18991 and consists of a base of granite on which rest the various 
formations of the Transvaal System, quartzites, dolomites, and banded 
jaspers, and the Matsap or Waterberg sandstone, unconformably 
above these. The rocks present a bewildering number of correlation 
difficulties and nearly all the low-lying ground is covered with the 
red Kalahari sand which obscures the junctions of the several systems 
of rocks. There are no rivers or stream beds with the exception of 
the Orange River, and all the water precipitated in the rare rains 
sinks through the sand and evaporates slowly leaving behind a crust 
of calcareous sinter. Weathering therefore is of the desert type, and 
the breaking down of the rocks is nearly entirely brought about by 
expansion and contraction, without chemical change of the constituent 
minerals. For this reason the less compact Permian and Triassic 
clays and shales of the Dwyka and Ecca Series have yielded easily 
to the forces of destruction and have been blown away; the under- 
lying rocks, however, of dense crystalline structure or of compact 
metamorphic nature, have emerged with relatively slight alteration 
from their burial beneath the Karroo rocks. The younger rocks were 
invaded by dolerite intrusions belonging to the great system of dykes 
and sills that extends right across South Africa almost from sea to 
sea, but the older are penetrated by a number of dykes of the most 
varying types which have been altered by crushing and metamorphic 
action generally so that they can be described as diabases, granulites, 
hornblende-schists, and serpentine with chrysotile. Besides these 
last there is a third class of intrusive rocks which is, paradoxically, 
amygdaloidal. 
These amygdaloidal melaphyres are known throughout the 
region of the Palafric rocks, whether we trace them on the surface 
in the Colony, Bechuanaland, or the Transvaal, or encounter them 
t Ann. Rept. Geol. Comm., Cape Town, 1900; see also E. H. L. Schwarz, Trans. 
Geol. Soc. S. A., Johannesburg, 1905, VII, and A. W. Rogers and E. H. L. Schwarz, 
“The Orange River Ground-Moraine,” Trans. Phil. Soc. S. A., Cape Town, 1900, IX. 
