242 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



therefore, most gratifying to me to learn that at length a 

 considerable portion of the lower jaw, with teeth, of an 

 Iguanodon, had been obtained from the quarry near Cuck- 

 field, in Sussex, in which the teeth of this colossal herbivorous 

 lizard were first discovered. 



In a communication addressed to the Royal Society in 

 1841, 1 I figured and described a fragment of the lower jaw of 

 a small reptile as, probably, that of a young Iguanodon, and 

 the anatomical considerations which seemed to support that 

 interpretation were fully detailed. But although, from the 

 form and the mode of implantation of the fangs, which are 

 the only vestiges of the teeth in the specimen, and the posi- 

 tion of the germs of the successional ones, this inference 

 appeared to me highly probable ; yet, as the crowns of the 

 teeth were wanting, the presumed generic identity could not 

 be established, since it was possible the fossil might belong to 

 the Hylseosaurus, or to some unknown genus of reptiles whose 

 bones occur in the Wealden deposits, as afterwards proved to 

 be the case. 



But the specimen to which I now solicit attention is the 

 right side of the lower jaw of an adult animal, with two suc- 

 cessional teeth in place, and the germ of a third, and the 

 alveoli or sockets of seventeen or eighteen mature molars, 

 and is the first indisputable portion of the jaw of the Iguano- 

 don which has hitherto been brought to light ; and although, 

 from the absence of mature teeth, and of the articular portion 

 of the jaw, this specimen does not afford a complete solution 

 of the problem discussed in the preceding pages, it pos- 

 sesses characters sufficiently definite and intelligible to throw 

 important light on the structure and functions of the dental 

 organs of the Iguanodon ; and it has also enabled me to 

 determine the nature of a portion of the left upper maxillary 

 bone, collected many years since, and now in the British 

 Museum, but which I was previously unable, to interpret. 



Before entering upon the description of this unique and 

 most interesting fossil, I must express my warmest acknow- 

 ledgments to Captain Lambart Brickenden, of Warminglid, 

 Sussex (now of Elgin, Scotland), by whom it was discovered, 

 and skilfully extricated from the sandstone in which it was 



1 " Philos. Trans." 1841, p. 131. 



