b 



BEilCflJKS, ETC., OF THE SOUTH OF ENGLAND. 307 



Mr. Topley refers to several instances in Kent and Sussex where 

 the gravel cannot be accounted for by river action/ and these he 

 refers generally to subaerial action or to the recession of the 

 Escarpment. 



Mr. W'hitaker places certain drifts in the London Basin amongst 

 those ' Doubtful Deposits ' which generally " have the appearance 

 of a local wash."," 



My object will be to show that these various drifts are probably 

 referable to the one and the same cause as that to which the Head 

 owes its origin. 



The intimate connexion of the Head with the Eaised Beaches is 

 merely accidental, owing to the circumstance that the angle between 

 the cliff and the beach formed a trough in which any debris 

 carried down from the hills above would necessarily lodge, just as it 

 would fill up any other indent on the surface over which it had to- 

 pass. Godwin- Austen has remarked that " these beds (the Head 

 over the Raised Beach) everywhere range inland, above and beyond 

 the level of the sea-beds on which they rest in the coast sections," ^ 

 but without specifying localities. 



We may take it as established that in every instance the character 

 of the rubble forming the Head depends entirely upon the character 

 of the local strata ; that, in the sense used when speaking of sedi- 

 mentary strata, it is always unstratified, and composed of sharp 

 angular fragments of the harder strata, and that it follows the slopes 

 of the hills, often furrowing the surface of, and extending for a 

 certain distance over, the adjacent valleys. As it recedes from its 

 base, however, it becomes subangular, and loses its calcareous 

 matter ; so that, as it ranges from the Chalk hills, the chalky 

 element gradually disappears, the flints lose their sharp angles, and 

 the insoluble loam or brick-earth, derived from outliers of Tertiary 

 beds, alone remains. It is on these characters, and on the fact that 

 it contains only land-shells and the remains of land-animals, that 

 we have to depend for tracing its range inland. To give all the 

 details of this drift in its many locations and phases would fill a 

 volume. I must therefore confine myself to a few illustrative 

 instances ; but it must be understood that there are few districts 

 in the South of England where traces of it are not to be found. 



(1) Upcliurch. — I would refer to this drift the plots of low-lying 

 gravel and brick-earth which lie in places at the base of the Chalk 

 hills, between Faversham and Chatham. Each of them has come 

 down one of the dry Chalk valleys which run up towards the escarp- 

 ment of the North Downs nearly to their summit, and debouch inta 

 the plain at their base, where they are independent of and subsequent 

 to the terraces of river-gravels. One of these narrow dry valleys 

 commences at Queen Down Warren, at an altitude of above 400 feet^ 

 and passes near Hartlip to the flat tract between the mainland and 

 the Isle of Sheppey, where its height is from 10 to 50 feet above 



1 ' Geology of the Weald,' pp. 168, 179, 183, 185, 201, 202. 



2 ' Geology of London,' vol. i. 3rd ed. p. 298. 



" Quart. Journ. Geol. Soc. vol. vii. (1851) p. 123. 



