i 40. VERTEBRAE OF THE IGUANODON. 



429 



deposit.* This discrepancy, however, does not affect the 

 arguments previously advanced, as to the fluviatile origin 

 of the strata of the Wealden ; it merely shows that part of 

 the delta had subsided, and was covered by the chalk ocean, 

 whilst the country of the Iguanodon was still in existence ; 

 and that the body of one of these reptiles was drifted far 

 out to sea, and sunk down in the depths of the ocean : in 

 like manner, as at the present day, bones of land quadrupeds 

 may not only be engulfed in the deltas of rivers, but also in 

 marine deposits far from land. 



This specimen proves that the separate bones found in the 

 strata of Tilgate Forest, and which I had assigned to the 

 Iguanodon, solely from analogy, have been correctly ap- 

 propriated. 



40. Vertebrae of the Iguanodon. — The peculiarities 

 in the vertebral column of the Iguanodon are pointed out 

 in the Medals of Creation, f and anatomical details would 

 here be irrelevant ; a few particulars must, however, be 

 noticed. The transverse processes of the dorsal and lumbar 

 vertebrae are very long and straight, indicating a consider- 

 able expanse of the abdominal cavity, suitable for the capa- 

 cious viscera of a herbivorous quadruped. In the caudal 

 vertebras, both the spinous processes (Lign. 105, a, «,) and 



* The stone in which the bones are imbedded is of that hard variety 

 of the grey, arenaceous limestone, called Kentish rag, which is much 

 employed in various parts of Kent, and in the west of Sussex, for 

 building, and for repairing the roads. It abounds in the marine shells 

 which are characteristic of that division of the chalk formation. In 

 the quarry in which the remains of the Iguanodon were found, there 

 have been discovered wood perforated by lithodomi, or boring shells ; 

 impressions of leaves and stems of trees, with trigonice, ammonites, 

 nautili, &c. ; conical striated teeth of the marine reptile called 

 Polyptychodon (ante, p. 354), some of which are two inches in diameter 

 at the base ; scales and teeth of squaloid fishes, and maxillary bones 

 of the Chimaera or Endaphodon of Sir P. M. Egerton. Molluskite 

 abounds in these strata. 



t Vol. ii. p. 745. 



