62 GEOLOGY OF THE ISLE OF WIGHT. 



tions, of extinct species and genera, and dissimilar 

 to those of the tertiary strata. 



IV. The wealden formation. — This is an 

 extensive series of clays, sands, sandstones, and 

 shelly limestones, upwards of 1,000 feet in thick- 

 ness, characterised by the entire absence of marine 

 fossils, and the abundance of river and lacustrine 

 fishes, crustaceans, and shells, intermingled with 

 bones of enormous land-reptiles, and terrestrial 

 plants and trees ; the whole group having evidently 

 been a vast delta. 



The essential characters, of these formations, and 

 of the subdivisions into which they are separated, 

 are concisely expressed in the annexed table. 



