It is interesting to observe the industry of many Boers in this region in making long and deep canals from lower levels up to spots destitute of the slightest indication of water existing beneath except a few rushes and a peculiar kind of coarse, reddish-colored grass growing in a hollow, which anciently must have been the eye of a fountain, but is now filled up with soft tufa. In other instances, the indication of water below consists of the rushes growing on a long, sandy ridge a foot or two in height instead of in a furrow. A deep transverse cutting made through the higher part of this is rewarded by a stream of running water. The reason why the ground covering this water is higher than the rest of the locality is that the winds carry quantities of fine dust and sand about the country, and hedges, bushes, and trees cause its deposit. 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 that 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 this part of the country during most of the year is of a light yellow color; for some months during the rainy season it is of a pleasant green mixed with yellow. Ranges of hills 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 flava') 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. Brunsvigia multiflora' (the former a poisonous bulb) yield in the decayed lamellae a soft, silky down, a good material for stuffing mattresses.
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 leveled in the proximity of a Bechuana village, no young trees spring up to take their places. This 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 the water, I found that it increased at the rate of a quarter of an inch in diameter annually during a number of years. Moreover, the larger specimens, which now find few or no successors, if they had more rain in their youth, can not be above two or three hundred years old.
It is probable that this is the tree of which the Ark of the Covenant and the Tabernacle were constructed, as it is reported to be found where the Israelites were at the time these were made. It is an imperishable wood, while that usually pointed out as the "shittim" (or 'Acacia nilotica') soon decays and wants beauty.