34 THE ORIGIN OF SOILS [chap. 



in the same district, the soil contains sand that has crept 

 from the central hills of the Weald or from the Lower 

 Greensand escarpment, often several miles away. The 

 following analysis of a soil resting on a brick earth 

 bed in the valley of the Kentish Stour, shows that the 

 brick earth, which itself contains little or no chalk, has 

 become covered with chalky rain-wash from the hills 

 flanking the valley : 



Depth Inches . . o to 6 6 to 12 12 to 18 18 to 24 

 Calcium Carbonate % 9-20 7-16 2-6 0-96 



In the main, however, the bed below gives its char- 

 acter, both chemical and physical, to the soil ; and the 

 ordinary rough classification of soils into sands, clays, 

 marls, and loams, follows closely the nature of the 

 underlying geological stratum. A coarse-grained 

 sandstone gives rise to a typically sandy soil, such as 

 the soils derived from the Bagshot beds, which form 

 the New Forest and the heathy land in the Aldershot 

 district ; on the Lower Greensand lie the sandy heaths 

 in west Surrey, Hampshire, and in Beds. ; again, on 

 the Bunter beds of the New Red Sandstone lie many 

 of the uncultivated commons and parks of the Midlands, 

 such as Sutton Park, Cannock Chase, and Delamere 

 Forest. These coarse sandy soils, which have so often 

 remained unenclosed as forests and commons, are gener- 

 ally deficient in chalk, and accumulate peat wherever a 

 parting of clay gives rise to stagnant water. 



Clay soils are common in nearly every part of 

 Britain ; they arise from the great clay strata of all 

 ages, like the London Clay, the Weald Clay, and the 

 Oxford Clay, or from metamorphic rocks like slate, or 

 from the crystalline rocks like granite and basalt, or 

 even from the limestones by solution. 



Between the sands and the clays come mixtures of 



