SOUTHERN AFRICA. 7 
vineyards, and orchards, that surround the habitations, where 
long culture, manure, and the fertihzing influence of springs, 
or a permanent rill of water, have so far mellowed the soil as 
to admit tlie spade at all seasons of the 3'ear. 
But those vast plains, which are known in the colony by the 
Hottentot name of Karroo, and which are interposed between 
t\ie great chains of mountains, wear a still more dismal appear- 
ance than the lower plains that are chequered with patches of 
cultivated ground. Out of their impenetrable surfaces of claj^ 
glistering with small crystals of quartz, and condemned to 
perpetual drought and aridity, not a blade of grass, and 
scarcely a verdant twig, occurs to break the barren uni- 
formity. The hills, by which the surface of these plains is 
sometimes broken, are chiefly composed of fragments of blue 
slate, or masses of felt-spar, and argillaceous ironstone ; and 
the surfaces of these are equally denuded of plants as those of 
the plains. 
Yet, as I have already observed, wherever the Karroo 
plains are tinged with iron, and where water can be brought 
upon them, the soil is found to be extremely productive. The 
same effect is observable in the neighbourhood of the Cape, 
where the soil is coloured with iron ; or when masses of a 
brown ochraceous stone (the oxyd of iron combined with clay) 
lie just below the surface, where they are sometimes found in 
extensive strata. In such situations the best grapes, and the 
best of every sort of fruit are produced ; which may be owing, 
probably, to the manganese that this kind of dark brown iron- 
stone generally contains, and which modern discoveries in che- 
