584 



THE WONDERS OF GEOLOGY. Lect. V. 



antecedent to the eocene, the earth was not adapted for 

 the existence of mammalia ? — that it was in a state of 

 turbulence and convulsion, which colossal reptile forms 

 were alone calculated to endure ; that it was a half-finished 

 planet, unsuitable for warm-blooded animals, and that its 

 atmosphere was incapable of supporting the higher types 

 of animal organization ? The probability that birds existed 

 in the country of the Iguanodon — the certainty that mar- 

 supial and insectivorous mammals were the contemporaries 

 of the Megalosaurus and Pterodactyles — that trees and 

 plants, of genera which now grow in regions abounding in 

 birds, and warm-blooded quadrupeds, flourished throughout 

 the " Age of Reptiles," are facts which appear to me fatal 

 to such a hypothesis, and to prove that the general tem- 

 perature of the earth, and the physical constitution of the 

 sea, and the atmosphere, were not essentially different from 

 those which now prevail. That the class of reptiles was 

 developed throughout the periods embraced in this review, 

 to an extent far beyond what has since taken place, cannot, 

 I conceive, by any legitimate process of reasoning be dis- 

 puted ; but I do not think that in the present state of our 

 knowledge, any satisfactory explanation of this extraor- 

 dinary fact can be offered. 



31. Objections considered. — There are persons who, 

 with one of the Bridge water essayists (Mr. Kirby*), 



* Seventh Bridge water Essay. In 1831, I transmitted a popular 

 summary of the evidence bearing on this highly interesting question, 

 with the title of " The Age of Keptiles," to Professor Jamieson, who 

 published it in the " Edinburgh Philosophical Journal." This un- 

 pretending paper brought upon mc an attack by the Rev. J. Kirby, in 

 his " Bridgewater Essay ;" in which the reverend author supposes that 

 there is a subterraneous world of reptiles, in which the Iguanodon 

 still nourishes ! ! and the occurrence of a vertebra of the Ichthy- 

 osaurus in diluvial gravel, is affirmed to be a proof of the modern 

 existence of that reptile ! ! ! As Dr. Buckland's Essay follows that of 

 Mr. Kirby, the reader has the bane and antidote both before him, and 



