﻿380 PROCEEDINGS OF THE GEOLOGICAL, SOCIETY. 



we proceed eastwards under the chalk-escarpment and reach another 

 marked depression, or that around Dorking, which like that of Pease 

 Marsh is contiguous to a great transverse fissure in the chalk, than 

 we again meet with detrital accumulations and the remains of fossil 

 quadrupeds, the bones of which were also found chiefly at the bottom 

 of the gravel. 



The Dorking Valley and the hollows around Deep Dene have been 

 for the most part swept clean of all stony debris and only fertilized by 

 loam ; but the low hills on the banks of the river Mole near Brock- 

 ham Green and Betchworth are partially covered with thick patches 

 of flint-drift, and it was in these localities that the fossil quadrupeds * 

 (Mammoth, &c.) were found, under a considerable mass of loamy 

 clayf. 



Other examples of accumulations of this nature have been long ago 

 described at Petteridge Common on the Weald-clay three miles south- 

 east of Reigate, and at Nutfield Marsh. On the north side of Til- 

 burstow Hill and at a very considerable height above the valley of 

 Godstone, the beds of chert of the Lower Greensand which are there 

 broken up for gravel, are covered by unstratified clay. In it are a few 

 minute fragments of chert, chalk, and flint, and I refer the whole to the 

 period of drift under consideration. 



Hitherto the drift under the scarp of the North Downs (as we pro- 

 ceed from west to east) has been chiefly spoken of, as either occurring 

 upon the Lower Greensand with its Neocomian (Atherfield) clay or 

 overlying formations, or upon patches of the Weald-clay which have 

 been denuded at no great distance from the Chalk-hills. From the 

 longitudinal meridian of Leith Hill, however, the drift begins to over- 

 lap the Weald-clay zone ; a fact precisely in accordance with what I 

 have noted on the southern side of the central dome. The facts 

 seem to indicate, in short, that on either side of the central dome 

 bodies of water have (as the Chalk and Greensand recede to the 

 south and north) necessarily overspread those portions of the Lower 

 Greensand and Weald-clay of Kent, which lay exposed in the line of 

 their transport. Thus the Weald-clay is covered at intervals either 

 with drift-loam or with debris of ironstone or chert of the Lower 

 Greensand ; and just as a large portion of the same clay on the south 

 side of the axis has been fertilized by this operation, so has the soil 

 been improved which occupies the tract extending from the south of 

 Bletchingley and Godstone to Eden Bridge. 



The most singular by far of all these collocations of drift in this tract, 

 is one which occurs on some dome-shaped hills of the Weald-clay 

 near its junction with the Hastings sands to the north of Hever 

 Castle, celebrated as the residence of Queen Anna Boleyn. There, 

 in two farms belonging to Mr. Waldo, the highest grounds, or those 



* See Mr. Morris's Note of the occurrence of these fossil bones, Loudon's Mag. 

 Nat. Hist. vol. ix. p. 46. 



f Immediately to the east of the station at Betchworth I observed that the 

 chalk-marl, which is there cut through, has been thrown into an undulation, much 

 denuded, and covered by a capping of loamy argillaceous drift with a very few 

 fragments of flint. 



