There is a rim or fringe of
ancient rocks round a great central valley, which, dipping inward, form
a basin, the bottom of which is composed of the oldest silurian rocks.
This basin has been burst through and filled up in many parts by
eruptive traps and breccias, which often bear in their substances
angular fragments of the more ancient rocks, as shown in the fossils
they contain. Now, though large areas have been so dislocated that but
little trace of the original valley formation appears, it is highly
probable that the basin shape prevails over large tracts of the country;
and as the strata on the slopes, where most of the rain falls, dip in
toward the centre, they probably guide water beneath the plains but
ill supplied with moisture from the clouds. The phenomenon of stagnant
fountains becoming by a new and deeper outlet never-failing streams may
be confirmatory of the view that water is conveyed from the sides of the
country into the bottom of the central valley; and it is not beyond
the bounds of possibility that the wonderful river system in the north,
which, if native information be correct, causes a considerable increase
of water in the springs called Matlomagan-yana (the Links), extends its
fertilizing influence beneath the plains of the Kalahari.

The peculiar formation of the country may explain why there is such
a difference in the vegetation between the 20th and 30th parallels of
latitude in South Africa and the same latitudes in Central Australia.
The want of vegetation is as true of some parts too in the centre of
South America as of Australia; and the cause of the difference holds out
a probability for the success of artesian wells in extensive tracts of
Africa now unpeopled solely on account of the want of surface water.
We may be allowed to speculate a little at least on the fact of much
greater vegetation, which, from whatever source it comes, presents for
South Africa prospects of future greatness which we can not hope for
in Central Australia. As the interior districts of the Cape Colony
are daily becoming of higher value, offering to honest industry a fair
remuneration for capital, and having a climate unequaled in salubrity
for consumptive patients, I should unhesitatingly recommend any farmer
at all afraid of that complaint in his family to try this colony. With
the means of education already possessed, and the onward and upward
movement of the Cape population, he need entertain no apprehensions