662 W. H. PENNING ON THE HIGH-LEVEL 
Karoo beds extend northward below them; any such additional 
beds would thin out against the Megaliesberg beds before reaching 
this part of the Vaal river. 
The shales and the trap-rocks, of course, weather very differently, 
the shales with a flat curve and rounded outline, the igneous rocks, 
when interbedded, forming steep ‘“ krantzes” or precipices; when 
occurring as dykes, with a rough stony outcrop resembling long 
lines of water-worn boulders. The rounded form of the loose stones 
is due to concentric decomposition and weathering ; this feature and 
their brown, frequently glazed, coating have together given rise to 
two wide-spread errors—that they are “ Ironstones” (as generally 
called), and that they are water-worn. Owing to this difference of 
weathering and the open nature of the country, beds and dykes may 
be distinguished by the eye, often for a distance of many miles, along 
the tops or flanks of the hills, although perhaps intersected by val- 
leys or by steep ‘‘ kloofs” (gorges), and falling into their proper place 
in outlying “ randts” and “ kopjes” (ridges and small hills). 
The “ High-Veldt beds” are mostly horizontal sandstones, en- 
closing seams of coal, and vary in texture and hardness from fine- 
grained crystalline sandstones to coarse grits and conglomerates, 
and from soft arenaceous beds to a hard rock resembling ‘“ Millstone 
Grit.” 
The general character of the lower coal-bearing part of the 
series will be gathered from the following sections; and it appears 
that similar beds occur to a great height above the lower beds, as 
the Sneeuwberg range (of which Compass Berg forms a part) con- 
sists of rocks of the same description. 
_ An estimate of the thickness of these beds may be formed in the 
same manner as that employed for the Kimberley beds, that is, 
after making a slight allowance for dip by the mere difference of 
elevation. The base of the series, north-east of Middelburg, is about 
5500 feet; the Compass Berg has an elevation of 8000 feet above 
the sea ; deducting 2U0 feet from the difference (for the rise in twenty 
miles, at 54, of a degree) the result gives a minimum thickness to 
the sandstone series of 2300 feet. 
