THEORY OF THE EARTH. 



this matter, in a Memoir upon the Ibis, which will 

 be found at the end of this Essay, and in which I 

 have shewn that it is still at the present day the 

 same as it was in the time of the Pharaohs. I 

 am aware that, in these, 1 only cite the monu- 

 ments of two or three thousand years ; but this is 

 the most remote antiquity to which we can resort 

 in such a case. 



There is nothing, therefore, to be derived from 

 all the facts hitherto known, that could, in the 

 slightest degree, give support to the opinion that 

 the new genera which I have discovered or esta- 

 blished among the fossil remains of animals, any 

 more than those which have in like manner been 

 discovered or established by other naturalists, the 

 palceotheria, anoplotheria, megalonyces, masto- 

 donta, pterodactyli, ichthyosauri, &c. might have 

 been the sources of the present race of animals, 

 which have only differed from them through the 

 influence of time or climate. Even if it should 

 prove true, which I am far from believing to be 

 the case, that the fosil elephants, rhinoceroses, 

 elks, and bears, differ no more from those at pre- 

 sent existing, than the present races of dogs differ 

 from one another, this would not furnish a suffi- 

 cient reason for inferring the general identity of 

 the species, because the races of dogs have been 

 subjected to the influence of domestication, which 

 these other animals neither did nor could expe- 

 rience. 2 



