272 BRITISH FOSSIL REPTILES. 



of the dental organs of the If/tianodon, their truth and beauty become still more manifest 

 as our knowledge of their svibject becomes more particular and exact. 



" In this curious piece of animal mechanism we find a varied adjustment of all parts 

 and proportions of the tooth, to the exercise of peculiar functions, attended by com- 

 pensations adapted to shifting conditions of the instrument, during different stages of 

 its consumption. And we must estimate the works of nature by a different standard 

 from that which we apply to the productions of human art, if we can view such 

 examples of mechanical contrivance, vmited with so much economy of expenditure, and 

 with such anticipated adaptations to varying conditions in their application, witliout 

 feeling a profound conviction that all this adjustment has resulted from design and 

 high intelligence." — (' Buckland's Bridgewater Treatise,' vol. i, p. 249.) 



In pursuing the search after the remains of Reptiles below the actual surface of 

 the soil, through the Formations of the Tertiary deposits in this island, it was found, as 

 has been shown in the First Section of the present Work, that the number and variety 

 of those remains rapidly increased when we had arrived at the oldest or " eocene " 

 division of the deposits ; the general character of the organic remains in which 

 demonstrate a warmer or more equable climate to have prevailed here during their 

 formation. Under conditions so favorable to the existence of the cold-blooded class 

 of air-breathing vertebrate animals, not only were the Reptilia larger and more 

 numerous, but they were distinct from any of the few small species now existing in the 

 British Islands ; and most of them belonged to orders which, as, e.(/., the Chelonia, are 

 either represented only by rare examples of the Marine Order, casually floated near or 

 cast on our shores, or which, as, e.g., the CrocodiUa, are no longer represented by any 

 indigenous species in Europe. 



All the species of Eocene Reptilia, nevertheless, belonged to orders and 

 families of the class which still exist in the warmer latitudes of the globe; and if some 

 of the fossils may seem to have been distinct from corresponding parts of actual 

 Genera, it was not from any of those great natural groups to which Linnaeus restricted 

 the term genus, but from the modern and less important sub-divisions of such, like 

 those into which the Linnean CoJubri have been dispersed, and to which sub-genera 

 the FalcEophis and Paleryx were correlative. 



In short, to the bottom of the Tertiary Deposits, or, in other words, from the very 

 commencement of that epoch in Geological time, we found only forms of the Reptilia 

 so little modified from those now existing as irresistably to impress us with the 

 conviction that they played the same parts, under very similar influences and circum- 

 stances, which are performed by the Gavials, Crocodiles, Alligators, Turtles, 

 Terrapenes, Mud Tortoises, Lizards, and Serpents of the present day. 



