112 VEGETATION. Chap. VI. 



The rushes in this case perform the part of the hedges, and the 

 moisture rising as dew by night fixes the sand securely among the 

 roots, and a height instead of a hollow is the result. While on 

 this subject it may be added, that there is no perennial fountain 

 in this part of the country, except those which come from beneath 

 the quartzose trap, which constitutes the " filling up " of the 

 ancient valley ; and as the water-supply seems to rest on the old 

 silurian schists which form its bottom, it is highly probable that 

 Artesian wells would in several places perform the part which 

 these deep cuttings now do. 



The aspect of tliis part of the country during most of the year 

 is of a light yellow colour ; for some months during the rainy 

 season it is of a pleasant green mixed with yellow. Ranges of 

 lulls appear in the west, but east of them we find hundreds of 

 miles of grass-covered plains. Large patches of these flats are 

 covered with white calcareous tufa resting on perfectly horizontal 

 strata of trap. There the vegetation consists of fine grass growing 

 in tufts among low bushes of the " wait-a-bit " thorn (Acacia 

 detinens), with its annoying fish-hook-like spines. Where these 

 rocks do not appear on the surface, the soil consists of yellow sand 

 and tall coarse grasses growing among berry-yielding bushes, 

 named moretloa (Grewia Jlava), and mohatla (Tarchonanthus), 

 which has enough of aromatic resinous matter to burn brightly, 

 though perfectly green. In more sheltered spots we come on 

 clumps of the white-thorned mimosa (Acacia horrida, also A. 

 atomiphylla), and great abundance of wild sage (Salvia Africana), 

 and various leguminosae, ixias, and large-flowering bulbs : the 

 Amaryllis toxicaria and A. JBrunsvigia multifiora (the former a 

 poisonous bulb) yield in the decayed lamellae a soft silky down, a 

 good material for stuffing mattrasses. 



In some few parts of the country the remains of ancient forests 

 of wild olive-trees ( Olea similis), and of the camel thorn (Acacia 

 giraffe), are still to be met with ; but when these are levelled in 

 the proximity of a Beclmana village no young trees spring up to 

 take their places. Tliis is not because the wood has a growth so 

 slow as not to be appreciable in its increase during the short period 

 that it can be observed by man, which might be supposed from 

 its being so excessively hard ; for having measured a young tree 

 of this species growing in the corner of Mr. Moffat's garden near 



