CONCLUDING OBSERVATIONS. 297 



2. 2. Chalk, constituting the South Downs of Sussex, the Surrey hills, 

 •and the North Downs of Kent. 



S. 3. Grey and Elue chalk marl ; at Kingmer, near Lewes, on the 

 north of the South Downs; at Bletchingley in Surrey, and Folkstone in 

 Kent, on the south side of the North Downs. 



4. 4. Green sand, and cherty sandstone ; at Eastbourne, south of 

 Lewes, Ditchling, Haslemere, &c. in Sussex ; near Godalming, Keigate, 

 Nutfield, &c. in Surrey ; Folkstone, and Hythe, in Kent. 



5. 5. Weald clay, containing Sussex marble ; Wealds of Surrey, 

 Sussex, and Kent. The locaHties of the hmestone in Sussex, are well 

 known ; in Surrey, it occurs at Eed-hill, near Reigate ; and in Kent, at 

 Bethersden. 



6. 6. Iron sand, with beds of bivalve limestone ; forming the central 

 range of hills on the boundary hue of Kent, and Sussex. 



7. Tilgate limestone, &c. 



The plan shews the appearance of the strata on the surface, and the 

 manner in which the various formations are disposed in regular succession 

 within the area encircled by the chalk hills, arranging themselves round 

 the central mass of Iron sand. Hence in the section from Newhaven to 

 the Forest ridge, the deposits form a descending series, and are incUned 

 towards the south ; thus we have 1. the Plastic clay, 2. the Chalk, 3. the 

 Blue chalk marl, 4. the Green sand, 5. the Weald clay, and 6. the Iron 

 sand. But proceeding from the Forest ridge to Dover, they are passed 

 over in an ascending order, and dip in a contrary direction ; the Iron 

 sand being the first, which is succeeded by the Weald clay, Green sand. 

 Blue chalk marl, and Chalk. 



Such is the geographical distribution of the strata in Surrey, Kent, 

 and Sussex ; and it is worthy of remark, that the formations on the op- 

 posite coast of France, are disposed in a similar manner, appearing hke a 

 continuation of the English beds. The escarpment of the French chalk 

 describes a semicircle of about twelve miles radius, ranging around Bou- 

 logne as a centre; the southern extremity, on the coast near Etaples, 



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