472 Annals of the South African Museum. 



Attention might be drawn here to the red sandy soil of Beclmana- 

 land as described by Rogers (1906). The sand is often of a deep 

 red colour, almost like brickdust, but on approaching an area in which 

 calcareous tufa predominates the colour is seldom so intense. An 

 examination of the material under the microscope shows that the 

 grains are more or less rounded, especially those of quartz, and vary 

 in diameter from a quarter to 1 mm. in diameter. The red colour 

 is due to a coating of oxide of iron, which is removed by boiling 

 with HG1. The great bulk of the material is composed of quartz 

 grains, which show trains of inclusions and cavities. Plagioclase is 

 not uncommon, and is present in the form of cleavage flakes, with 

 the angles somewhat worn. Chalcedony and agate are rather rare; 

 zircon and magnetite are abundant, while epidote is a common con- 

 stituent. The composition of the sand shows that it has not been 

 derived from the disintegration of the rocks of the district alone. 

 The felspar and magnetite have been contributed by the disintegration 

 of dolerites. It is probable that the quartz grains have been brought 

 down from the Transvaal and the Orange Free State, Cape and 

 Basutoland by the Vaal, Harts and Orange Rivers. The sand depo- 

 sited along river-l>anl<s will be blown over the country by the pre- 

 vailing N.\V. wind. The decomposition of the diabase and dolerite 

 and of pyrites in shales yield compounds of iron which can be taken 

 into solution and deposited as oxide in the cracks and cleavages of 

 the sand grains and around the grains themselves. 



In the Red Beds of the Stormberg Series we find that save for 

 occasional blue clays and whitish sandstones at the base, the various 

 members are all red in colour. Carbonates occur, sometimes freely, 

 as nodules, and in places form beds of limestone. 



In the Maclear division, for example, the sandstone is commonly 

 full of porous patches or small hollows representing spots originally 

 rich in calcareous material, with here and there limestone nodules. 

 Gypsum and salt are absent - - a feature which distinguishes the beds 

 from the Wichita Series of Texas. Conglomerates are rare, such as 

 do occur being generally at the base of the formation. 



At the base of the sandstone layers, however, bands of clay-pellet- 

 conglomerate are not uncommon. Such bands indicate a certain 

 amount of unconformity, the clay-pellets being formed by the rolling 

 and rounding of the possibly dessicated upper layers of partly con- 

 solidated mudstone which lie beneath the sandstones. That the mud 

 was dried by exposure before successive sediments were laid upon 

 it is indicated by the occurrence of layers showing sun-cracks (cf 

 examples in the South African Museum from Fouriesburg, O.F.S.); 



