274 PROCEEDINGS OF THE GEOLGOICAL SOCIETY. [May 19, 



Origin of the Soils which cover the Chalk of Kent*," combated the 

 dogma, that these soils were formed by solution of the rock in situ, 

 and that the non-calcareous varieties are the residuum of such hypo- 

 thetical solution. 



In opposition to these views I contended, that such soils were 

 formed by aqueous transport of some kind or other, the nature of 

 which I did not then attempt to define ; nor do I now attempt to de- 

 fine it beyond this : that, if atmospheric, it was different from ordi- 

 nary atmospheric action ; if marine, it was different from ordinary 

 marine action; that the phsenomena produced were different from 

 those which, in the case of the Till or lower erratics, I attribute to 

 the action of shore-ice on sinking land, and different from those which, 

 in the case of the sand and gravel of the upper erratics, I attribute 

 to the action of ice floating in a more open sea. 



Neither do I now attempt to define the date of these operations in 

 Kent, beyond this : that many of the phsenomena are closely allied 

 to, if not identical with, those which, north of the Thames, took place 

 after the desiccation of the bed of the glacial sea, and after pleisto- 

 cene England had been re -inhabited by some of the large mammals, 

 now extinct, which had flourished in pliocene England, before its 

 submergence beneath the glacio-pleistocene sea. 



In proof of the formation of the soils on the chalk of Kent by 

 aqueous deposit, I adduced a section in which a road-cutting, near 

 Hartley Rectory, exhibited irregular alternations of dark tenacious 

 clay containing unabraded flints, with light-coloured sandy loam and 

 seams of rounded eocene pebbles. That section was on the descent 

 towards a valley communicating with the valley of the Darent, from 

 the elevated plateau of chalk which extends to the Weald denuda- 

 tion. It has therefore been argued that this section, being on the 

 slope of a hill, merely represents an accumulation of the nature of a 

 talus, although I stated that similar deposits constitute the surface- 

 soil for miles on the summit of the plateau. 



I shall now draw attention to the soils on some of the highest 

 summits of the chalk, at an elevation of about 700 feet, near the edge 

 of the precipitous escarpment overhanging the Weald denudation, or, 

 more correctly, the Vale of Holmsdale, lying between the chalk and 

 the Wealden. 



By reference to the Ordnance Map it will be seen, that the road 

 from Farningham to Wrotham ascends the chalk from the valley of 

 the Darent, along a combe. The steep side of the combe is covered 

 with calcareous soils, for the most part white, but intermixed 

 with some irregularly distributed patches of loams, light-coloured, 

 brown, and of various intermediate shades of colour, but all more or 

 less calcareous. The summit attained, these calcareous soils cease, 

 and are replaced by dark brown non-calcareous loams, of depths va- 

 rying from less than one to more than three feet, and of various de- 

 grees of tenacity. About the fourth mile from Wrotham, the tena- 

 cious varieties prevail. They appear to belong to that class of soils, 

 which Boys, the author of the Report on this County, describes as 



* Loc cit. 



