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immediately above decomposing basalt, it may be de- 

 nominated basaltic soil. If fragments of quartz and 

 mica be found abundant in the materials of the soil, 

 which is often the case, it may be denominated granitic 

 soil ; and the same principles may be applied to other 

 like instances. 



In general, the soils, the materials of which are 

 the most various and heterogenous, are those called 

 alluvial, or which have been formed from the deposi- 

 tions of rivers ; many of them are extremely fertile. 

 I have examined some productive alluvial soils, which 

 have been very different in their composition. The 

 soil which has been mentioned page 163, as very pro- 

 ductive, from the banks of the river Parret in Somer- 

 setshire, afforded me eight parts of finely divided 

 earthy matter, and one part of siliceous sand ; and an 

 analysis of the finely divided matter gave the follow- 

 ing results. 



360 parts of carbonate of lime, 



25 alumina, 



20 silica, 



8 oxide of iron. 



19 . vegetable, animal, and saline matter. 



A rich soil from the neighbourhood of the Avon, 

 in the valley of Evesham in Worcestershire, afforded 

 me three fifths of fine sand, and two fifths of impalpa- 

 ble matter ; the impalpable matter consisted of, 



35 Alumina, 



41 Silica, 



14 Carbonate of lime, 

 3 Oxide of iron, 

 7 Vegetable, animal, and saline matter. 



