§ 34. SWANAGE FOSSIL CROCODILE. 415 



completely filled up ; hence, at whatever age a tooth may 

 be removed, there is found, either in the socket, or in the 

 cavity of the tooth itself, a new germ, in a greater or less 

 state of advancement, ready to occupy the place of the old 

 one, when the latter shall be removed; and this succession 

 is often repeated. In this fossil tooth (Lign. 100) from 

 Tilgate Forest, the internal series of cones is exposed, in 

 consequence of the removal of the outer case of the old 

 tooth. Numerous fossil teeth, possessing this character, 

 have been obtained from the wealden ; they are separable 

 into two kinds. 



The first is from an inch to two inches in length, of a 

 slender acuminated form, laterally compressed, and gently 

 recurved, with a thin edge in front and behind ; resembling 

 in appearance a tooth of the Megalosaurus (Lign. 101), 

 with the serrated edges worn off.* Some biconcave ver- 

 tebra?, with compressed w^edge-shaped centres, f are supposed 

 to belong to the same reptile, which has been named Sucho- 

 miwus cultridens.% The other form of tooth has a cylin- 

 drical base, and an obtusely conical crown with numerous 

 longitudinal grooves and ridges, and a sharp line on each 

 side ; a specimen, attached to a small block of sandstone, 

 is represented Lign. 100.§ 



34. Swanage fossil crocodile. — The teeth last de- 

 scribed are comparatively of frequent occurrence in the 

 wealden of the south-east of England, and are often 

 associated with dermal, or skin-bones, which are the 

 osseous supports of the thick horny scutes or scales of the 

 integument of mail, with which the Ga vials and other 



* Medals of Creation, vol. i. PL VI. fig. 7. Fossils of Tilgate Forest, 

 PI. V. fig. 10. 



f Fossils of Tilgate Forest, PI. IX. fig. 11. 



I British Association Eeports for IS 41, p. 6§. 



§ Medals of Creation, vol. i. PI. VI. fig. 5. Fossil* of Tilgate Forest, 

 PI. V. figs. 1, 2, 9. 



