C 179 3 
VIII. J^otice on the Iguanodon, a newly discovered fossil reptile y 
from the sandstone of Tilgate forest, in Sussex. By Gideon 
Mantell, F. L. S. and M. G. S. Fellow of the College of 
Surgeons, &c. In a Letter to Davies Gilbert, Esq. M. P. 
V. P. R. S. &c. ^c. &c\ Cornmunicated by D. Gilbert, Esq, 
Read February lo, 1825. 
Sir, 
1 AVAIL myself of your obliging offer to lay before the Royal 
Society, a notice of the discovery of the teeth and bones of a 
fossil herbivorous reptile, in the sandstone of Tilgate forest ; 
in the hope that, imperfect as are the materials at present 
collected, they will be found to possess sufficient interest to 
excite further and more successful investigation, that may 
supply the deficiencies which exist in our knowledge of the 
osteology of this extraordinary animal. 
The sandstone of Tilgate forest is a portion of that exten- 
sive series of arenaceous strata, which constitutes the iron-sand 
, formation, and in Sussex forms a chain of hills that stretches 
through the county in a W. N. W. direction, extending from 
Hastings to Horsham. In various parts of its course, but 
more particularly in the country around Tilgate and St. Leo- 
nard's forests, the sandstone contains the rknains of saurian 
animals, turtles, birds, fishes, shells, and vegetables. Of the 
former, three if not four species belonging to as many ge- 
nera are known to occur, viz. the crocodile, megalosaurus, 
plesiosaurus, and the iguanodon, the animal whose teeth 
