66 9 



were not determined, although they were present in Miiall quantities. 

 Good t'ertile soils in Kurope contain from 'i to '43 per cent, of phos- 

 phoric aeid, and from -i to '2 per cent, of potash. These soils are 

 more liable to be depleted of their phosphoric acid than their potash. 

 In the soils of this colony the potash appears to be less in quantity 

 than the phosphoric acid ; except in such places where the white 

 gum and morrell gum are found growing, there the potash is from 

 one to three times the amount of the phosphoric acid. It will also 

 be noted that where the iron, alumina and potash are in large propor- 

 tions in these soils, the lime decreases. No. 3 might appear to be an 

 exception, but it is not, it is a limestone subsoil which has had some 

 of the potash from No. 2 washed into it. That the lime should be 

 low when the potash is high, and the potash high when the lime 

 decreases, will appear natural, when we consider the composition of 

 the rocks that the soils are formed from. The soils are chieily made 

 up from the granite or the trap rocks, or a mixture of both. Granites 

 are mainly composed of quart/ and felspar. The soil from granite 

 will depend for its fertility on the class of felspar the granite con- 

 tains ; whether it is a potash felspar (orthoclase), a soda felspar 

 (albite) or a magnesia felspar (oligoclase). 



The late Professor Anderson gives the following analyses of 

 these felspars : 



The trap rocks are composed of felspar and hornblende. 

 Sometimes augite replaces the hornblende. No matter which of 

 these is in combination with the felsite, it will be seen from the 

 following analyses that a soil made from the decomposition of such 

 a rock would naturally be a complete and fertile soil, so far as its 

 mineral constituents are concerned. 



