III. GRANITE SOILS. f 



Phosphoric 

 Division. Farm. Fine earth. Water. Lime. Potash. oxide. 



George. Diepkloof. 94'7 "97 "028 '034 '020 



Malmesbury. Alexanderfontein. 720 T57 "146 '121 '061 



73'8 1-15 '072 '075 '072 



800 1-47 '096 '095 '073 



72-2 I'Ol '014 -114 "049 



680 1-09 '014 -045 "028 



76-0 1-28 -014 -095 "055 



Paarl. Vredehof. 61'5 "87 '034 '014 "055 



Stellenbosch. Neethlingshof. 691 T26 '024 '023 '018 



The averages of these soils work out as follows : 



Lime '049 



Potash '069 



Phosphoric oxide '048 



The result of the partial decomposition of the felspar contained in 

 the granite is seen in the relatively larger percentage of potash when these 

 analyses are compared with those of the clay slate soils, and to such a> 

 cause may also be due the relatively large proportions of potash in the 

 two Hooge Kraal soils of the Malmesbury series. 



More recent, geologically, than the slates of the Malmesbury series, 

 are what have been termed the Cango beds, in the Oudtshoorn Division. 

 They consist of quartzitic pebbles embedded in a slaty matrix, which at 

 some places becomes calcareous. It may be expected that the former 

 type will produce a comparatively poor soil, while a correspondingly 

 better class of soil will be produced where the calcareous matrix prevails. 

 Unfortunately, the sandstone range of the Zwartbergs so overshadows 

 the localities whence were collected the only three of our samples which 

 represent the area of the Cango beds, that the exact extent to which they 

 typify these beds caomot yet be arranged. The following are the three 

 soils referred to : 



IV. CANGO BEDS. 



Phosphoric 

 Division. Farm. Fine earth. Water. Lime. Potash. oxide. 



Oudtshoorn. Lemrick. 58'6 111 '068 194 123 



Welgevonden. 76'0 T90 "084 144 '067 



Matjes Eivier. 61' 6 315 7'460 "087 166 



Nothing need be said to lay stress on the great difference between 

 the first two and the last of these three soils. 



We have now to turn our attention to a class of soils of still more pro- 

 nounced calcareous type. As in the south-western corner of the Colony 

 the pre-Cape rocks comprise largely the Malmesbury clay-slates and shales, 

 so in the northern part we have the series of rocks which, over thirty 

 years ago, Stow associated with the name of the Campbell Rand,* and 

 into the composition of which limestone and dolomite enter largely. In 

 the soils representative of this series we would consequently expect to find 

 large quantities of lime. Here and there, however, the effects of the 



* Seepage 143. 



