§32. CROCODILIAN REPTILES. 413 



are eight inches in the transverse diameter of the articular 

 face, and but four and a half in the antero-posterior length 

 of the body of the vertebrae.* 



These reptiles must have rivalled the living Whales in 

 bulk, for some specimens indicate a length of forty or fifty 

 feet ; they are supposed to have had web -feet, and a broad 

 vertical tail. | The bones found in the Wealden may have 

 been transported from the sea by the tide, or the living ani- 

 mals may have occasionally been carried far up the river, 

 as is sometimes the case with the modern cetaceans. 



32. Crocodilian reptiles of the Wealden. J — The 

 loricated or mailed saurian reptiles, as the Alligators, Croco- 

 diles, and Gavials, of which numerous remains occur in the 

 eocene strata, are well known as the largest existing forms 

 of oviparous quadrupeds. 



No relics of any living species have been observed in the 

 secondary strata, but several allied genera appear to have 

 flourished during these epochs. But the crocodilians of these 

 ancient types differed materially in structure from the modern; 

 and particularly in the vertebral column, which in one fossil 

 genus only is composed of concavo-convex vertebrae, and 

 these are in a reversed position ; the ball or convexity of 

 the bone being directed forwards, or anteriorly, instead of 

 in the contrary direction, or posteriorly, as is the case in 

 the living Crocodiles. 



As a general character, it may be stated that the croco- 

 dilians with broad muzzles, as the Cayman and Alligator, 

 do not occur in a fossil state below the eocene deposits ; all 

 the reptilian remains of that family in the secondary fornia- 



* I discovered a fine suite of four consecutive vertebras in the sand- 

 stone of Tilgate Forest, and succeeded in extricating them entire from 

 the rock. One of these vertebrae is figured in Philos. Trans, for 1841, 

 PI. IX. fig. 13. 



f British Association Keports, 1841, p. 102. 



£ Medals of Creation, p. 718. 



