Vol. 62.] IN THE SOUTH-WEST OF CAPE COLONY. 73 



little soil on the hills, the bare rock in most cases showing through. 

 The bushes were originally the woody Karroo-bushes, which force 

 their roots down in the crevices formed by surface-expansion and 

 contraction, and the necessary soil exists only in these small 

 fissures ; a useless, imported, rhenoster-bush, however, is dis- 

 placing the natural vegetation, to the great detriment of the 

 country. In the east, the vegetation grows on a thick, sandy 

 soil, and consists of grasses, sedge-like plants, proteas, heaths, 

 and many of the beautiful Cape-iris family. The ruggens-veld is 

 sweet veld, but the heath-country is sour. 



Beneath the sand on the sour veld there commonly forms an 

 ironstone, due to the action of water dissolving out iron-compounds 

 from the rocks, and this shuts off the roots of the plants from the 

 substratum of rock ; where this is granite, which contains the finest 

 mineral foods for plants, such as lime, phosphates, and potash, 

 the surface-vegetation is as poor as that on the Table-Mountain 

 Sandstone, which is made up of pure silica with scarcely a trace 

 of argillaceous matter. If, by any chance, the soil is removed from 

 off the ironstone-gravel, the latter hardens on exposure to a massive 

 bank of ironstone; it is then what is sometimes called laterite, 

 although there is no alumina to render the application of the term 

 strictly correct. 



The deposits on this coastal plateau have given rise to much 

 controversy, and their nature seemed so essentially that of river- 

 deposits, that for a long time the plain was thought to be a base- 

 level of river-erosion. In Komgha, in the extreme east of the 

 Colony, some of the freshwater quartzite was found to contain 

 seeds of Ghara, thus pointing to the fact that the deposit was 

 formed in fresh water. But it does not necessarily follow in this 

 particular case, because the deposit on the plain is evidently fresh- 

 water, that consequently the plain itself must have been cut by 

 river-action; for Mr. W. Anderson l has recorded Ghara-seeds in a 

 deposit on the shores of a lagoon on the Zululand coast, which lies 

 evidently on a plain of marine denudation that has just emerged 

 from the surface of the ocean. 



In Caledon and Swellendam, where the width of the plateau is 

 some 15 or 20 miles, and the seaward end shut off by a series of 

 outstanding hills, the problem is complicated ; but, standing on the 

 top of a peak of the Zitzikamma Mountains, and surveying the ledge 

 at one's feet, which is only some 3 or 4 miles broad, it seems 

 impossible that rivers coursing down from the mountains could, in 

 so short a distance, acquire that sluggishness and lack of velocity 

 which would be required to enable them to cut their channels 

 sideways, and level the rugged country. There is no possibility of 

 invoking a different cause for the levelling in the two places, for the 

 same plateau is continuous, right away from the western end of 

 Caledon to the town of Port Elizabeth ; the same level, the same 

 gradient of fall from the mountains to the sea, the same general 



1 2nd Eep. Geol. Surv. Natal & Zululand, London, 1904, p. 51. 



