158 



silicate of alumina, and, therefore, practically void, not only of actual 

 plant food, but even of plant food constituents. 



Attention is directed chiefly to the percentage proportions of lime, 

 potash, and phosphoric oxide in the soils, but there are also incorporated 

 in the list the percentages of moisture retained in the air-dried soils : this 

 is expressed in terms of the soil sifted through a 1 mm. sieve, while the 

 determinations of plant food are calculated upon the fine earth. The 

 percentages of this fine earth in the sample, as collected in the field and 

 air-dried, are also given below. 



Division. 

 Cape. 



Paarl. 



Stellenbosch. 



Farm. 



Hooge Kraal. 







Matjes Kuil. 

 Groenfontein. 

 Kuilenberg. 



Lange Bug. 

 Knolle Vallei. 







Driefontein. 

 Burgers Drift. 

 Dryvers Vallei. 

 Lange Hoogte. 

 Elsenburg. 



Nooitgedacht. 



I. MALMESBURY SERIES. 

 Fine earth. Water. 



821 

 82-4 

 51-0 

 81-2 

 53-6 

 551 

 65-3 

 79-6 

 68-7 

 50-6 

 60-3 

 51-8 

 55-8 

 80-2 

 57-7 

 92-2 



1-78 



1-33 



29 



67 



1-13 



1-72 



Til 



1-72 



32 



52 



1-20 



1-48 



63 



95 



63 



81 



Lime. 



608 

 107 

 024 

 012 

 072 

 100 

 034 

 098 

 012 

 022 

 026 

 014 

 010 

 065 

 044 

 008 



These Malmesbury series soils, it will be noticed, exhibit, almost 

 throughout, an all-round poverty in plankfood. The first on the list, 

 however (which is No. 33 of the Cape Division soils, whereof some details 

 were given on page 43), stands out markedly from the rest 

 on account of its higher plant-food content. The pebbles associated with 

 this soil point to its being derived from a rock of almost uniformly dull 

 greenish grey tint, and differ clearly from the various coloured fragments 

 found in connection with the next soil (No. 34), which includes brighter 

 red sandy ironstone* and white quartz. The unusual richness for thia 

 part of the country of the former soil makes it desirable to trace its geo- 

 logical horizon more closely, but for the present, owing to imperfect know- 

 legde of the sequence within the Malmesbury series, it must suffice to 

 record the existence therein of beds capable of producing soils of more 

 than ordinary quality. The percentages in the above sixteen soils 

 average as follows : 



Omitting the 

 All-inclusive, first two soils. 



Lime 



Potash 



Phosphoric oxide 



079 

 124 

 039 



039 

 039 

 039 



Commencing near the village of Robertson, a tongue of the Malmea- 

 bury beds runs at first westward for about thirty miles, and afterwards 

 northwards, as a depression between two sandstone ranges, for a distance 

 of nearly forty miles, forming the Tulbagh valley. (See sketch map at- 

 tached.) As will be pointed out later on, when dealing with the soils of 

 the Table Mountain series, the soils of the northern portion of this valley, 

 being practically encircled by mountains composed of Table Mountain 



* Some of which contain flakes of white mica (muscovite) pointing to granitic origin. 



