672 W. H. PENNING ON THE HIGH-LEVEL 
It falls gradually across the northern rivers and along the Vaal 
to above Bloemhof, from 5000 to 3500 feet. 
And (as shown on fig. 3, p. 661) from the Cape Colony to the 
same point, from 5500 to 3590 feet. 
3. This approximate coincidence of the outcrops and contour- 
lines all around the high-level coal-fields, broken only by local 
fractures, indicates the continuity of beds similar to those exposed 
at the outcrop throughout the intervening area, interrupted pro- 
bably by local disturbances, but quickly resumed. Therefore it 
may be safely concluded that seams of coal equal to those exposed 
in the sections occur (with small local exceptions) over the whole 
of the vast area upon the map *. 
4, Although there is no evidence from deep shafts or borings, it 
is more than probable that there are many seams at different hori- 
zons in the lower part of this formation. This is indicated by the 
occurrence at different levels of horizontal seams, without any indi- 
cation of faults between, as, for instance, in the sections about the 
head of the Wilge river.. 
5. The relative position of the basal plane at any point may be 
approximately ascertained by drawing a line through that point to 
the outcrop on either hand, and allowing for the proportionate rise 
or fall. The depth to the lowest coal-bearing rocks at such point 
will be the difference between the height of the basal plane thus 
ascertained and the surface-elevation. 
Discussion. 
Prof, T. Rupert Jones remarked that it was unfortunate that all 
Mr. Stow’s observations had not yet been published in detail. Inthe 
present paper the author had brought together many useful observya- 
tions; but he thought it was to be regretted that each writer on 
South-African geology should think it necessary to make alterations 
in the names applied to the deposits. Mr. Bain’s “ Great Karoo” 
formation had by degrees nearly disappeared. 
Mr. W. T. Braxrorp said that there were two points in the paper 
to which he thought attention should be called. One was practical. 
The evidence of the seams scarcely justifies the conclusions stated 
as to the mineral wealth of the country. Jt is an error to suppose 
that beds of coal are continuous over great distances because they 
are so throughout comparatively small areas. Moreover, the 
quality and thickness of seams are very variable even over moderate 
areas, especially when the roof is of sandstone. Then as to the 
geology :—these beds are spoken of as lacustrine, but he thought 
there was no evidence upon this point, and that the beds are more pro- 
bably subaerial and fluviatile. He could not agree with the author, 
* In Dr. Atcherley’s book, ‘A Trip to Boer-land,’ I find that at p. 220 he 
says :—‘ There can be little doubt that the whole High Veldt is one immense 
coal-field.” 
