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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



Lower Greensand on which Seven Oaks is situated, on which much 

 drift has been arrested, and through which there is no transverse 



opening. 



Looking therefore to the present configuration of the land, it is 

 impossible that any great ancient river following the direction of the 

 present streams could have transported these materials. Whether, 

 then, they came from the fracture of the Darent, or were translated 

 from the greater rupture and depression in the chalk north of Maid- 

 stone, in both cases they must, unlike the Petersneld drift (p. 356), 

 have been carried in a direction completely opposed to the present 

 drainage of the lands. They must, in short, have either been trans- 

 lated over intervening hills or up the present valley of the Medway. 



The loam-drift with flints extends indeed all down the banks of the 

 Medway to Maidstone*, and, occasionally spread over flats, is exposed 



* Since this memoir was read. I made an excursion to Maidstone, to ascertain 

 if the distribution of the drift in that neighbourhood were similar to that cited 

 from other localities along the escarpments of the South and North Downs. This 

 examination completely confirmed my views, in showing the extensive diffusion of 

 the detritus of the Chalk, over the hills of Greensand and Kentish Rag, and thence 

 extending to the Weald-clay. It is manifest that the whole of the rocks of the 

 tract, where the Medway escapes through a grand transverse fissure and denuda- 

 tion in the Chalk, have been most powerfully broken up and dislocated. Not 

 only is the surface of the Upper Chalk deeply eroded, and filled with red drift (there 

 600 feet above the sea), but huge, loose masses of the grey-wether tertiary beds 

 have been hurled down the escarpments and lodged on the surface of the Lower 

 Chalk, where the largest of them have been raised by the early Britons into 

 " Cromlechs." Some loose flints are spread over the Low 7 er Chalk ; but the valley 

 of Gault is clean-denuded. On the other hand, the northern side of Pennenden 

 Heath and the Chalk-escarpment have arrested considerable quantities of flint- 

 gravel, which increase in thickness as you approach the summit, about 200? feet 

 above the sea. Fossil bones of Mammoth, Rhinoceros, Hippopotamus, Stag, 

 Horse, &c. t have been found, as I was informed by Mr. Bensted, in the excavation 

 of brick-earth and flint-drift on the slopes above the Jail at Maidstone, which I 

 had examined, and not less than 80 feet above the river. Dr. Plomley indeed 

 gave me specimens of the teeth of Rhinoceros tichorhinus which had been found 

 there. Freshwater and Land Shells also occurred in some of the overlying loam, 

 and the whole case is therefore precisely in accordance with that of other places 

 cited. No one can separate this drift of the summits of Pennenden and Barming 

 Heaths from the bone-drift of Maidstone. 



There are few districts in the South-East of England which better merit a de- 

 tailed, monographic description than that around Maidstone, where the extraordi- 

 nary curvatures and fractures of the Kentish Rag (each anticlinal line being more 

 or less parallel to the bends of the Medway) and the tumultuous infillings of drift 

 in the cavities of the numerous quarries offer the most striking confirmation of 

 my views. Mr. Bensted, whose discoveries are w r ell-known to geologists, was so 

 obliging as to point out to me, a rapid anticlinal of the grit near Aylesford, where 

 the overlying flint-drift seemed to be conformable to the strata which dip off at 

 an angle of 55°; whence it might be inferred that the movement which produced 

 this flexure w'as even posterior to the deposition of the flint-debris. If it be cer- 

 tain that the drift has been tilted by an upheaval of the rock beneath, then this is 

 a case analogous to that observed by Mr. Austen near Guildford. In the Aylesford 

 case, however, I have still some doubt on the point ; as in an adjacent quarry to the 

 north, where the Kentish Rag has undergone another contortion, the inclined strata 

 of grit are in contact with gravel, which has a sort of rude horizontal bedding. 

 However this may be, one feature at the same locality is too remarkable to be 

 passed over in silence. The surface of the upheaved grit (there very cherty) has 

 been bored into by Pholades, and if these shells should prove to be of existing 



