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depositions of rivers; many of them are extremely 
fertile. I have examined some productive alluvial 
soils, which have been very different in their com- 
position. The soil which has been mentioned 
page 160, as very productive, from the banks of 
the river Parret in Somersetshire, 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 following results. 
860 parts of carbonate of lime. 
25 — alumina. 
20 — silica. 
8 — oxide of iron. 
19 — vegetable, animal, and saline mat- 
ter. 
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 impalpable matter ; the impalpable matter con- 
sisted of, 
35 Alumina. 
41 Silica. 
14 Carbonate of lime. 
3 Oxide of iron. 
7 Vegetable, animal, and saline matter. 
A specimen of good soil from Tiviot-dale, 
afforded five-sixths of fine siliceous sand, and one- 
sixth of impalpable matter ; which consisted of 
41 Alumina. 
42 Silica. 
4 Carbonate of lime. 
5 Oxide of iron. 
8 Vegetable, animal, and saline matter. 
