Representative Transvaal Soils. 



171 



Soils Nos. 1267 and 1620 are from the Mngnliesberg quartzites, 

 No. 1485 is derived from the Uaspoort, and No. 2554 from the Time- 

 ball Hill quartzites. 



These sand particles on being washed clear of the finer soil 

 particles appear as more or less rounded quartz grains with peculiar 

 little red and yellowisli pits. The pits are probably due to the removal 

 of part of the iron ore. On the whole the soil is much too open and 

 sandy, but its texture may vaj-y somewhat, when the true type is 

 infiuenced by the adjacent diabase rocks or beds of shales, or, con- 

 tinuous cultivation and the incorporation of organic matter have 

 improved and altered its physical properties. 



Mechanical Coviposition.—3elow are given the complete 

 mechanical analyses of two of these quartzite soils: — 



No. of Sample 



1901. 



2179. 



Stones 



Moisture... 



Loss on ignition (organic matter) 



Fine gravel 1 to 8 m.m. in diameter ... 



Sand 0*2 to 1-0 m.m. in diameter ... 



Fine sand 0*04 to 0"2 m.m. in diameter 



Silt 0-01 to 0-04 m.m. in diameter ... 



Fine silt 0'004 to 0*01 m.m. in diameter 



Very fine silt U"0()2 to 0*004 m.m. in diameter 



Clay smaller than 0*002 m.m. in diameter containing 



Iron oxide soluble in acid 



Alumina... 



No. 1901 is a samj^le of red sandy soil from Zuurplaats No. 822, 

 Rustenburg District, and is derived from the Magaliesberg quart- 

 zites. 



No. 2179 is a brown sandy soil from Koedoespoort No. 299, 

 Pretoria District, and is derived from the Daspoort quartzites. 



There is no marked difference in the mechanical analyses of 

 these two soils. They both contain a high percentage of sand, very 

 little clay, and less than 3 per cent, organic matter; consequently 

 their water retaining capacity is very small, the analyses showing 

 them to contain only about A per cent, of moisture. 



Sample No. 1901 is slightly coarser in texture than is sample 

 No. 2179, since while the former contains 77.2 per cent, of the two 

 coarser fractions fine gravel and sand together, and only 8.4 per cent, 

 of very fine silt and clay, the latter contains lesg'tha'n 70 per cent.. 



