152 Morton^ Nature and Property of Soils. 



the surface, than by any other means whatever. While we state 

 this, we readily admit that the geological and chemical study of 

 soils is of very great importance with reference to their improve- 

 ment ; and that, without a considerable degree of this kind of 

 knowledge, no man need attempt to improve an unproductive 

 soil, so as to render it permanently productive. The author of 

 the little work before us has adopted the following mode of treat- 

 ing his subject. He commences by observing that 



" The surface of the earth partakes of the nature and colour of the subsoil 

 or rock on which it rests. 



*' The principal mineral in the soil of any district is that of the geological 

 fofmation under it ; hence, we find argillaceous soil resting on the various clay 

 formations — calcareous soil over the chalk — and oolitic rocks, and silicious 

 soils, over the various sandstones. On the chalk, the soil is white ; on the 

 red sandstone, it is red ; and on the sands and clays, the surface has nearly 

 the same shade of colour as the subsoil. 



" The lime, potash, and iron, existing in various proportions in the rock, 

 are acted on by the atmosphere, and the rock is decomposed ; some of it into 

 fine impalpable matter, some into sand, and some into coarse gravel or 

 rubble. 



" The surface is composed of the same materials as the subsoil, with the 

 addition of vegetable and animal matter, in every state of decay, intimately 

 mixed with it ; and we perceive a change in the external appearance of the 

 surface, whenever there is a change in the subsoil below. 

 ■ " The similarity of the materials which compose each of the geological 

 formations with those which compose the soil resting on it, will be easily dis- 

 cerned ; and their seeming difference may be owing to the vegetable and co- 

 louring matter in the soil. Iron, on being exposed to the atmosphere, becomes 

 oxidised, forming the oxide of iron, and gives a redder colour to the soil than 

 that which is exhibited by the subsoil. 



" The connexion which subsists between the soil and the subjacent rock or 

 stibsoil is, in our opinion, of great importance, as a knowledge of it would 

 form the best foundation for a classification of soils ; and would always convey 

 some idea of the nature and quality of the materials of which the soil is com- 

 posed." 



He next gives an outline of the main body of each of the 

 geological formations in England, and its connexion with the 

 surface. These formations consist of earths of transportation ; 

 alluvial soil ; diluvi'um ; peat moss, or bog ; London clay ; plas- 

 tic clay ; chalk formation ; green sand formation ; gault ; oak 

 tree, or Weald clay ; iron sand, or Hastings sand ; coral rag, 

 calcareous grit, Aylesbury and Portland stone ; the Oxford, 

 clunch, or fen clay ; oolite formation ; inferior oolite, and calcare- 

 ous ferruginous sand; blue lias ; new red sandstone, or red sand ; 

 magnesian limestone; coal formation ; millstone grit; carboni- 

 ferous, or mountain, limestone ; old red sandstone ; greywacke 

 and clay-slate ; granitic formation ; basaltic rocks. The descrip- 

 tions of these formations, and the notices respecting their agricul- 

 tural character, occupy upwards of one hundred pages. 



The classification of soils is next treated of; and this is done 

 more in what may be called a practical manner, with reference to 



