310 PitOP. J. PKESTWICH OX THE RAISED 



hills to near Cob Tree ^ and Aylesford, where it lies against the 

 base of the hill capped by a bed of high-level mammaliferous river- 

 drift. 



How far the brick- earths around Maidstone are connected with 

 drift, and how far with river-floods, I am not prepared to say. I 

 have, however, a growing conviction that large sections of the brick- 

 earths in the South of England are connected with this drift. I 

 would, for example, place with it the high-level (290 feet) brick- 

 earth south of East Mailing, that at Crown Point (490 feet) near 

 Ightham, and of Seal Chart Common (529 feet), as also that described 

 by Mr. Topley north-west of Sevenoaks. 



(6) Sevenoahs, Sfc. — In the Sevenoaks district it is probable that 

 some of the drifts I termed • hill-gravels ' are of this date."-^ The 

 mass of Lower Greensand debris covering the slope of Sheet Hill 

 near Ightham is certainly a debacle from the high Greensand range 

 immediately behind. The slopes of Oldbury Hill are covered with 

 debris and blocks from its summit, and on the northern side large 

 blocks lying in a loamy or clayey bed follow the course of the valley 

 for some distance northward. The angular chert-rubble on the 

 slope of the hills by Seal Chart, and the thick bed of the same in 

 the valley between Bessel's Green and Sundridge, may be of the 

 same age, while to the south of the Greensand Escarpment the 

 traces of it are fewer, and include probably those high patches 

 north of Tunbridge mentioned by Mr. Topley,^ and composed of 

 angular fragments of chert. Of these he remarks that they are 

 " apparently not all true river-gravel, but merely subaerial deposits 

 left by the recession of the Lower Greensand escarpment." Again, 

 speaking of the Ouse basin, he says, " Elints are occasionally found 

 lying over the surface of the Weald Clay in this district. These are 

 not connected with river-gravel, but are probably the remains of the 

 Chalk which once covered the whole area." ^ 



(7) Guildford. — Another remarkable exhibition of this drift in 

 the adjacent county is that described by Col. God win- Austen in 

 a section of the railway on the London road east of Guildford,* 

 which I had the advantage of visiting with him. The railway has 

 cut through a high-level terrace of the old river Wey, consisting of 

 stratified sands and gravels, resting at one end on Woolwich and 

 Reading Beds, and at the other on Chalk. The section is nearly 

 half a mile long, 20 feet deep, and its base is 64 feet above the level 

 of the Wey. The fluviatile drift consists mainly of Lower Green- 

 sand debris, which was evidently carried from the south through the 

 gorge of the Chalk hills at Guildford. About midway in the cutting 

 a coarse unstratified drift of Chalk and angular flints sets in over 



^ It there contained the plate of an Elephant's tooth, which may, howeveiv 

 kaye been derived from the adjacent high-level gravel. 



2 Quart. Journ. Geol. Soc. vol. xlv. (1889) p. 275. 



3 ♦ Geology of the Weald,' p. 185. 



* Ibid. p. 202. I have before given my objections to this view ; see Quart, 

 Journ. Geol. Soc. vol. xlvii. (1891) p. 158. 

 5 Ibid. vol. xl. (1884) p. 599. 



