240 Professor Pictet on Fossil Bones. 



sion is confirmed by the examination of fifteen species of mam- 

 mifera, and three of reptiles. We may, in my opinion, draw 

 from this the following consequences. 



I can here find, in the first place, a proof of the law of the 

 permanence of species. Among the principal arguments on 

 which this important principle rests, that most frequently in- 

 sisted upon is the comparison of the animals preserved in the 

 ancient sculptures of Egypt with the existing species. When 

 we perceive that the lapse of four thousand years has pro- 

 duced no modification of form, not even the slightest, on the 

 skeletons of crocodiles, ibises, cats, ichneumons, &c., we are 

 authorised to deduce from the fact the general law that the 

 species invariably preserve their characters. The bones pre- 

 served in our gravels are undoubtedly still more ancient 

 than those of Egypt, and, therefore, furnish a more positive 

 proof of this. But what more particularly gives them a 

 greater degree of interest, is what has been often alleged, 

 namely, that, while we admit the permanence of species in 

 the present state of the globe, we may likewise allow that, 

 at periods of great geological changes, more active forces, 

 and more intense atmospheric alterations, may have caused 

 more important modifications in organism. The fossil spe- 

 cies of our diluvian deposits have assisted at one of these geo- 

 logical changes ; they have inhabited our valley before the 

 deposition of the gravels, and yet they have continued un- 

 changed until our own day. Do we not thus obtain, at least, 

 a presumption, that it is the same in such cases in general ; 

 and may we not draw from this an argument in favour of the 

 much more probable opinion, that great geological events 

 have killed and destroyed the species, but could not produce 

 any modification in their forms % 



I believe, in the second place, that we may find in these 

 facts, a proof that our diluvian deposits are more recent than 

 those of the greater part of Europe. The bones which I have 

 examined, belong, as I have stated, to the diluvian forma- 

 tions of our valley, and, yet all the species to which they can 

 be referred are still alive. Now, the greater part of the 

 European diluvian deposits enclose the bones of elephants, 

 rhinoceroses, and other .species now extinct. Such is like- 



