3/0 CRETACEOUS. 



The Kentish Rag limestone is in some parts replaced by dark chert. At Seven- 

 oaks there is a bed of chert above the Kentish Rag called the Sevenoaks Stone, 

 which is much used for road-mending. Chert (locally called ' whinstone') has 

 been dug near Petworth ; at this locality and at Pulborough, hard sandstones (Pul- 

 borough Stone) in the Hythe Beds have been worked since the time of the 

 Romans. 



Fuller's Earth occurs in places ; it has been dug at Tillington. Phosphatic 

 nodules occur in the Hythe Beds near Godalming. 



The soil as a rule is light, stony, and sandy, and in many places is particularly 

 adapted to the growth of Hops. Over large areas there is much wood- and 

 common-land covered with heath and fir. 



Sandgate Beds. 



This term was proposed by Mr. Drew in 1861, from the develop- 

 ment of the beds at Sandgate, near Folkestone. (See Fig. 60.) 

 It has been remarked that the beds form a low cliff of a blackish 

 green colour between Folkestone and Sandgate, and they extend 

 inland to Hythe. They consist of dark clayey sand and clay ; the 

 dark colour is due to green particles of glauconite (hydrous silicate 

 of iron, potash and alumina). At the junction with the Hythe beds 

 there is occasionally a band of phosphatic nodules and pebbles, 

 with fragments or casts of fossils and bored wood. 



At Sandgate the beds are 80 feet in thickness, and comprise the 

 following strata : — 



Brownish clays. 



Yellowish-green sands. 



Black clayey sand. 



Dark greensand. 



Black sands (zone oi RhyiicJionella sulcata).'^ 



The Sandgate Beds contain Coniferous wood ; the Annelide 



Vermicularia concava ; Brachiopoda, Rhynchonella Gihhsia7ia, etc. 



Mollusca, Gervillia anceps, Cucullcea glabra, Panopcea {Myacites) 



plicata, Cytherea parva, etc. Bones of Ichthyosaurus campylodon 



have also been found. 



The Sandgate Beds are not persistent over the Wealden area ; at 

 Maidstone their thickness is fourteen feet, and they are not with 

 certainty represented at Godalming. (See p. 369.) At Pulborough 

 they attain 100 feet, as sand and shale ; and at Petersfield they are 

 represented by about seventy-five feet of sand capped by dark 

 sandy clay. 



Some discussion has arisen concerning the position of the Fuller's Earth, 

 whether it should be grouped with the Hythe Beds or even with the Folkestone 

 Beds, but it is placed with the Sandgate Beds by the Geological Survey. The 

 typical district of the Fuller's Earth is near Nutfield and Redhill or Reigate. 

 Here, it is true, the beds do not resemble the Sandgate Beds of the coast, a 

 circumstance which has led to some doubt as to their exact position in the series. 



^ F. G. H. Price, P. Geol. Assoc, iv, 137. 



