662 Journal op the Department of Agriculture. 



contains much less silt than No. 614 — more fine silt and a little more 

 clay. No. 610 contains rather less organic matter than No. 614 and 

 rather less humus. One concludes that although there is a resemblance 

 between the two soils No. 614 has the better physical make-up. 



Considered chemically. No. 610 and No. 614 also show close 

 agreement, excepting that No. 610 contains much less total phosphoric 

 oxide. Considering the fineness of the texture of tlie latter soil one 

 is inclined to think that, notwithstanding the fair amount of avail- 

 able phosphoric oxide it contains, it would respond to phosphatic 

 manuring. [See remarks on page 437 concerning the action of 

 phosphoric oxide on the development of roots.] Like most of the soils 

 of the Witkop area, No. 610 is acid to litmus, a condition that may 

 be corrected by the application of agricultural lime. 



A comparison of the figures for insoluble inorganic residue in 

 soils Nos. 610 and 607 is not without interest, for, if due allowance 

 be made for their different content in moisture and in organic matter, 

 the figures are nearly identical (viz., 89.1 per cent, and 88.5 per 

 cent.), which suggests that the mineral skeleton of the soils has a 

 common origin and that the present mechanical ond chemical 

 differences revealed by analysis originate in the steeper gradients 

 laound No. 607, and in the iiresence under the latter at no great depth 

 of a calcareous water which has given the soil an alkaline reaction 

 and has led to the accumulation of a valuable quantity of humus. 

 While it can be expected tha+ liming, phosphatic manuring, and 

 green manuring would do much to improve No. 610, it is not to be 

 expected that there is any ])racticable method by which it could be 

 made to equal No. 607. 



Witkop axd Ki; aaifoxteix : Mk. 1). \. Kan.nkmfaer. 



Reference to the geological map on page 353 will show the posi- 

 tions of Kraaifontein and Witkop relative to Kalkfontein, as well as 

 their geological characteristics. 



The portions of Witkop and Kraaifontein with which we are 

 concerned are in the kloof, reference to which was made on page 356. 



The kloof bottom is of Molteno Beds, while its head and cliffs are 

 of Eed Beds. It is to be noted that tlie spruit which passes down the 

 kloof drains an area of volcanic beds situated at the southern corner 

 of Witkop ; also that dolerite dykes occur on both sides of the kloof, 

 one of them passing through the kloof. 



The homestead of Witkop is situated in the kloof at a distance 

 of less than a mile from its head and at an altitude some 250 feet 

 lower than the plateau on which Witkop Post Office stands. Near 

 the head of this kloof are some caves which contain some fine samples 

 of Bushman art. 



The soil of the upper part of the kloof, viz., from the homestead 

 upwards is of a rich black colour near the spruit, becoming browner 

 the further one gets away from the water-course. No. 617, a com- 

 posite sample of virgin soil, was derived from a land close to the 

 spruit, and not far above the homestead. 



The vegetation of the neighbourhood consists of kamfer bos, 

 blauwsaad, and kweek grasses, together Avith, here and there, a clover 

 plant. If left undisturbed the land becomes quickly covered with 



