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CHAPTER VII. 



Formations yielding Soils of Clayey, Free, Poor, and Rich Character Review 

 of Indications of Fertility Differences between Quality and Value of 

 Land Sedentary and Transported Soils Peat Soils Volcanic Soils 

 Methods of Improving Soils Land Drainage Reasons for its Usefulness. 



ALL soils, from whatever geological formation derived, have 

 certain points in common. They all are composed upon the 

 general principle or general arrangement of proximate con- 

 stituents already named. All contain a certain variable 

 proportion of soluble plant food. All are made up of the 

 four or five familiar substances, sand, clay, lime, and vegetable 

 matter interspersed with mineral fragments. And again, 

 upon every formation good land and bad land, and in very 

 many cases light land and heavy land is to be found. 



But, while this is the case, it is equally true that there is 

 a leading character which runs through soils derived from 

 the principal formations, either as regards the general contour 

 of the districts, and consequently of the soils resting upon it, 

 or it may be the fertility or non-fertility of these soils. 

 Certain geological formations may be spoken of as usually 

 characterized by the presence of heavy land, for example the 

 London, the Weald, the gault, the Kimmeridge, the Oxford, 

 and the lias clays. All these yield soils of stiff character. 

 On the other hand, in certain formations light, easy-working 

 soils predominate, more suitable for sheep-farming in com- 

 bination with arable cultivation ; as, for example, the soils 

 of the upper chalk, of the lower oolite, of the magnesian 

 limestone, and of the Yoredale rocks and the millstone grit. 



