454 On tlie Agricidtui^al Geology of England and Wales. 



extent, A communication is also insisted on bet^Yeen the dilu- 

 vial tracts and the rocks under or near them, though it is admitted 

 that this is not alwavs the case. 



Three diluvial form.ations are described: — I. The diluvium 

 resting on the chalk, referred to the wreck of the eocene ter- 

 tiaries. This is described as consisting in some places of little 

 else than flints ; in some^ as in Dorsetshire, of flinty gravel ; in 

 others, as in Kent, Surrey, Sussex, Hampshire, and Berkshire, of 

 red tenacious clay, with rolled flints, varying in some instances 

 to a loamy clay or to sand and gravel. 2. Diluvium of the new 

 red, described as occurring in detached portions^ often of con- 

 siderable thickness, on that rock and on the coal measures, 

 usually consisting of sand, but occasionally composed of clay. 

 3. The diluvium of the gault and Oxford clay, which may be 

 traced through Lincolnshire and Northamptonshire into Wilt- 

 shire and Gloucestershire. Other minor diluvial accumulations 

 are spoken of, consisting of local gravels, occupying limited and 

 detached areas at the mouths of the deep valleys which intersect 

 the oolitic hills, never as constituting deep deposits and assuming 

 the form of hills like the diluvium of the new red. The sand and 

 gravel, as well as the clay with fragmentary chalk, which cover 

 the greater part of Norfolk and Suffolk, referred by other 

 geologists to the diluvium, are regarded by Mr. Morton — we 

 must add erroneously — as members of the plastic clay series. 

 Of alluvial soils it is said, that as the materials of which they are 

 composed depend entirely on the geological formation through 

 which the rivers flow, of course the nature and property of the 

 alluvium in each river or country may differ entirely from that 

 of another. 



Starting from these principles, Mr. Morton traces the changes 

 of the different formations as laid down in geological maps, and 

 describes in general outline the nature of the soils on each of the 

 stratified and unstratified rocks. While certain general charac- 

 ters are ascribed to the soils on each formation, considerable local 

 variations are admitted, which are assumed to be dependent on 

 variations in the mineral composition of the rock beneath. Some 

 of the specified variations, however, referred to this cause we 

 know, from personal observation, to depend on the distribution 

 of the superficial deposits. 



The plastic clay of Essex, for instance, is described as yielding 

 a reddish-brown clay on a clay subsoil, while in some places, as 

 at Chelmsford, it yields a sandy loam, and a good turnip soil. 



Indeed," it is added, " every variety of soil may be met with on 

 this formation, which is owing to the rapid succession of sand and 

 clay, and the other materials of which it consists." The cause 

 of these variations will be noticed hereafter. To this formation 



