§ 4. THE WEALDEN. 365 



to the southern shores of the Isle of Wight, in San- 

 down Bay, we shall have the section represented in 

 Lign. 78, which exhibits the entire series of the de- 

 posits, and their relative position in the south-east of 

 England. 



The older tertiary or eocene strata, forming the site of 

 London, are seen occupying a depression of the chalk ; the 

 North Downs of Surrey next appear — then the anticlinal 

 ridge of the Wealden — the South Downs of Sussex and 

 Hampshire succeed — covered on the south by the marine 

 tertiary strata of Southampton — then the depression in the 

 strata occupied by the Solent — the north of the Isle of 

 Wight covered by fresh-water and marine eocene deposits — 

 next the vertical chalk range of the Island — and, lastly, the 

 emergence of wealden beds from under the greensand, in 

 Sandown Bay.* 



4. The Wealden. — The tertiary basin of London 

 afforded an example of the accumulation of detritus and 

 organic remains in an inland sea ; — that of Paris, of marine 

 and fresh-water sediments, deposited in a gulf open to the 

 sea on the one side, and fed by rivers and thermal springs 

 on the other ; — the lacustrine formations of Auvergne, of 

 the gradual precipitation of strata in the tranquil waters of 

 lakes ; — the cretaceous formation, of the operations which 

 have taken place in the profound abyss of an ocean ; — 

 while the series of deposits to which the term Wealden is 

 applied, presents the most striking instance of an ancient 

 delta hitherto discovered. Yet strange as it may appear, 

 although these strata occupy the whole area between 

 the North and South Downs — a tract of country traversed 

 daily by hundreds of intelligent persons from the metro- 

 polis — their peculiar characters were entirely unknown 

 twenty-five years ago ; the whole group being then sup- 



* See Geology of the Isle of Wight, p. 74. 



