IGUANODON. HYL^OSAURUS. 185 



SECTION X. 



IGUANODO N.* 



As the reptiles hitherto considered appear from their teeth 

 to have been carnivorous, so we find extinct species of the 

 same great family, that assume the character and office of 

 herbivora. For our knowledge of this genus, we are in- 

 debted to the scientific researches of Mr. Mantell. This 

 indefatigable historian of the Wealden fresh-water forma- 

 tion, has not only found the remains of the Plesiosaurus, 

 Megalosaurus, HylasosauruSjf and several species of Cro- 

 codiles and Tortoises in these deposites, of a period inter- 

 mediate between the oolitic and cretaceous series, but has 

 also discovered in Tilgate Forest the remains of the Iguano- 

 don, a reptile much more gigantic than the Megalosaurus, 

 and which, from llie character of its teeth, appears to have 

 been herbivorous.J The teeth of the Iguanodon are so pre- 



* See PI. 1, F\)r. 45, and PI. 24 ; and Mantell's Geology of Sussex, and of 

 the soQlIi-east of lOngland. 



t The Hylaeosaurus, or Lizard of tlie Weald, was discovered in Tilgale 

 Forest, in Sussex, in 1832. This extraordinary Lizard was probably about 

 twenty five feet long^. Its most peculiar character consists in the remains 

 of a series of lon^r, fl;it, and pointed bones, which seems to have formed an 

 enormous dermal friiigCi liiie the horny spines on the back of the modern 

 Iguana. These bones vary in length from five to seventeen inches, and in 

 width from three t > seven inches and a half at the base. Together with 

 them were found the remains of large dermal bortes, or thick scales which 

 were probably lodged in the skin. 



t The Iguanodon has hitiierto been found only, with one exception, in the 

 Wealden fresh-water formation of the south of England, (PI. 1, section 22.J 

 intermediate between the marine oolitic deposites of the Portland stone and 

 those of the green-sand formation in the cetaceous series. The discovery, 

 in 1834, (Phil. Msg. July, 1834, p. 77.) of a large proportion of the skeleton 

 of one of these animals, in strata of the latter formation, in the quarries 

 «f Kentish Rag, near Maidstone, shows that the duration of this animal 



16* 



