232 Dr. MantelVs Isle of Wight. 





edge at present extends, not a single species is known either in 

 the tertiary strata or in more recent deposits : with the chalk the 

 whole race of the ammonites disappeared. With respect to the 

 vegetable kingdom of the cretaceous period, the presence of nu- 

 merous marine fuci attests the nature of the marine flora ; and 

 the fragments of drifted coniferous wood, fir-cones, stems and 

 leaves, which are found in the flint and chalk in some localities, 

 prove that the dry land was clothed with pine forests and cyca- 

 deous plants. The occasional discovery of bones and teeth of 

 reptiles, shows that the islands and continents were tenanted by 

 oviparous quadrupeds. Of birds and mammalia not a vestige has 

 been discovered. 



The Weald en Formation, so ably investigated by Dr. Mantell 

 and other English geologists on the opposite coast of England, 

 has been fully made out in the Isle of Wight, and we may there- 

 fore presume that it is continuous beneath the English channel 

 The clays and fresh-water limestones and beds of lignite of the 

 Wealden, are found at Sandown and Compton bays in this island, 

 and the limestones contain both bivalves and univalves. Petri- 

 fied trees are found in great abundance at Brook Point, some- 

 times retaining the ligneous structure, at other times in the form 

 of a coally black matter or filled with pyrites. The trees are all 

 lying postrate and appear to have been accumulated under water 

 like the rafts of the Mississippi. Some of the trees lying along 

 the shore are three feet in diameter, and appear to have been 

 covered when in a state of maturity. Two stems were traced 

 to a length of twenty feet, and indicated trees from forty feet to 

 fifty feet long while living. The annual and annular lines of 

 growth are often very distinct, and bear a close resemblance to 

 the Auracaria or Norfolk Island pine. Thirty or forty have been 

 traced on a single stem ; they are all of unequal thickness, thus 

 indicating the variation of the seasons in heat and moisture. 

 The wood was mineralized by calcareous and not by siliceous 

 matter, and the bark was generally turned into lignite. 



11 In the clays for several hundred yards, both to the east and 

 west of Brook Point, bones of the Wealden reptiles are numerous ; 

 with these are associated large mussel shells and lignite.' 7 



Among the fossil reptiles the bones of the colossal Iguanodon 

 are conspicuous, an animal whose former existence was firs 1 

 proved by Dr. Mantell. These bones are washed out by the sea 

 and strewed along the shore, subject to the destroying action oi 

 the waves, and are in general water-worn masses of bone id- 

 eating the enormous magnitude of the animals to which they 

 belonged. The bones are generally impregnated with * r0 ?T 

 often garnished with brilliant crystals of pyrites, and the medul- 

 lary cavities filled with calcareous spar. The bones collected 

 within the last few years in Sandown, Brixton, Brook, and 



