J28 TRAVELS IN 
The foils, in general, on this tra£t of country, are either of 
ftiff clay, into which there is no poffibility of entering with a 
plough till well foaked by heavy rains, or of a light and fandy 
nature, commonly of a reddifh tinge, and abounding with fmall 
round quartzofe pebbles. Seldom any free black vegetable 
mould appears except in the fmall patches of garden ground, 
vineyards, and orchards that furround the habitations, where, 
by long culture, manure, and the fertilizing influence of fprings 
or a permanent rill of water, the foil is fo far mellowed as to 
admit the fpade at all feafons of the year. 
But thofe vaft plains, which are known in the colony by the 
Hottentot name of Karroo^ and which are interpofed between 
the great chains of mountains, w^ear a ftill more difmal appear- 
ance than the lower plains that are chequered with patches of 
cultivated ground. Out of their impenetrable furfaces of clayj 
gliftering with fmall chryftals of quartz, and condemned to per- 
petual drought and aridity, not a blade of grafs, and fcarcely a 
verdant twig, occurs to break the barren uniformity. The hills, 
by which the furface of thefe plains are fometimes broken, are 
chiefly compofed of fragments of blue flate, or mafl!es of felt- 
fpar, and argillaceous ironftone ; and the furfaces of thefe are 
equally denuded of plants as thofe of the plains. 
Yet, as I have already had occafion to obferve, wherever the 
Karroo plains are tinged with iron, and water can be brought 
upon them, the foil is found to be extremely produdlive. The 
fame eflfe^l is obfervable in the neighbourhood of the Cape, 
where the foil is coloured with Iron j or where mafles of a 
I brown 
