268 GEOLOGY OF THE ISLE OF WIGHT. 



buried beneath the whole is a petrified forest of 

 pine-trees with cycadeous plants, still erect in the 

 soil in which they grew ; and in all these deposits 

 bones of colossal terrestrial reptiles are more or 

 less abundant. The upper clays and limestones oc- 

 cupy the valleys of the Wealden districts that skirt 

 the inner escarpments of the chalk downs in Surrey, 

 Kent, and Sussex ; the middle group of sands and 

 sandstones constitutes the Forest-ridge of those 

 counties ; and the lower series appears in the deep 

 valleys in the east of Sussex, around Battel, Bright- 

 ling, Burwash, and Ashburnham. The Purbeck 

 strata, which are characterised by thick beds of 

 shelly limestone principally formed of a small 

 species of paludina, appear on the coast of Dor- 

 setshire, in the Island, or more properly the Penin- 

 sula, whence the name is derived. The Wealden 

 presents the most perfect example of an ancient 

 delta hitherto discovered ; in the numerous for- 

 mations comprised in the systems of Geology, 

 there is no other instance of so well defined and 

 extensive a group of fluviatile deposits.* 



* Scarcely twenty-five years ago, though the Wealden districts were 

 traversed daily by hundreds of intelligent persons in their journeyings to and 

 from London and Brighton, their freshwater origin was unsuspected; the 

 whole group being considered by Geologists as identical with the sands, 

 clays, &c. of the chalk formation. For though the shells forming the Sussex 

 marble of the weald clay, were supposed, so long since as Woodward's 

 time, to be fluviatile species, yet this point was controverted by some able 

 eonchologista ; and but lew if any other organic remains bad been obtained 



