Minutes of Proceedings. vii 



practically identical in nature with those found in the ** heavy 

 wash " of the Eiver Diggings of the Vaal River, nevertheless it did 

 not appear to him necessary to assume that the pebbles had been 

 drifted from the mouth of the Orange River. The fact that the 

 pebbles appeared to have a very restricted distribution on the shore 

 of the island seemed rather to favour the assumption of a local 

 origin for the pebbles. 



Mr. W. T. Saxton read a short summary of his communication 

 " On the Development of the Oviary and Embryo-sac in Cassia 

 tomeiitosay 



Mr. C. F. JuRiTz communicated a paper on ''The Fertility of 

 Some Colonial Soils as Influenced by the Geological Conditions." 



Chemical analyses of the soil may be of three different types, 

 according as they show (1) how much plant-food exists in a form 

 immediately available for plants, (2) what proportions are present as 

 a reserve stock, or (3) the aggregates of the plant-food constituents 

 in the soil. The third type of analysis may have its value for the 

 geologist, but only the first and second afford the farmer any 

 indications of the land's worth, the former indicating its immediate 

 productiveness and the latter its permanent value. 



Until recently sufficient samples had not been analysed by a 

 method that could be taken as a reliable means of ascertaining the 

 reserve stock of plant-food in the Colony's soils, nor had the 

 Geological Commission progressed to an extent sufficient to enable 

 it to be used as a working basis. Furthermore, the soils that had 

 been analysed had been selected from definite fiscal divisions without 

 regard to geological conditions. Some 200 soils had, however, been 

 selected from the number hitherto analysed and taken as fairly 

 representative of various geological formations. 



Of the soils derived from the Pre-Cape rocks, those from the 

 Malmesbury slates in the South- Western part of the Colony were 

 found to be poor all-round on the average. In the northern portion 

 of the country where the Campbell Rand series extended over a 

 large area the soils were rich in lime. 



The soils derived from the Table Mountain series, which were 

 the lowest rocks of the Cape system and consisted of little 

 else than silica, lacked all the essential mineral ingredients of 

 plant-food. 



Above the Table Mountain series lay the Bokkeveld beds, and 

 these produced soils with satisfactory proportions of plant-food. 



The highest rocks of the Cape system, namely, the Witteberg 

 series, produced soils which may be anticipated to resemble those of 

 the similar Table Mountain series, and the few that had been analysed 



