GEOLOGY. 295 



certain. The examination of a treatise on palaeontology is sufficient 

 to show that the existing species are already indicated in the Dilu- 

 vian deposits. 



The terrestrial and fluviatile mollusks are in the same category. 

 Thus with the bones of the Elephas primigenius are frequently found 

 buried all our species of Helix, Bulimus, etc.. and they show us that 

 for the invertebrata, as well as for the vertebrata, all the existing 

 fauna date from the origin of the Diluvian period. 



The preceding facts suffice to show that there has been no renewal 

 of the fauna between the Diluvian period and the modern epoch. 

 We must now consider in what consists the apparent difference which 

 has led most geologists into error. It has been caused by the gradual 

 disappearance of a certain number of species. At the commence- 

 ment of the Diluvian period the fauna was richer and more complete 

 than it is at present. There lived in Europe at that time not only 

 our present animals, but a certain number of species which are now 

 extinct. These latter have gradually disappeared, from causes prob- 

 ably in part similar to those which destroyed one species of ox men- 

 tioned by Julius Caesar, and which destroyed most likely the last 

 representatives of the ure-ox (aurochs) and the elk. The fauna of 

 the Eastern continent has been successively impoverished, and as the 

 population and cultivation of the soil increased, only a part of the 

 species which once dwelt there remain living. 



It is not possible, in the present state of palaeontology, to prepare a 

 complete and precise catalogue of these extinct species ; but it is suf- 

 ficient for our purpose to. sketch the principal features of such a cata- 

 logue. 



I have experienced some doubt in regard to many races or species 

 of true Quaternary deposits, indicated as different from those now 

 living, bt which have been characterized without doubt by their 

 form, and not by appreciable organic characters. It appears to me 

 quite natural that species at the commencement of the Diluvian 

 epoch, finding abundant nourishment in a country where great forests 

 and immense virgin territories replaced our present culture, and 

 being able there to develop in freedom, should have frequently had a 

 form a little superior to their existing representatives, which, sur- 

 rounded by hunters, restrained on every side, lead a more difficult 

 and precarious life. I do not think it possible to give a specific value 

 to slight differences of stature, if all the other characters are identi- 

 cal, and therefore I consider as doubtful many of those species in- 

 serted in the catalogues of palaeontology. Such are the Talpa fos- 

 silis, the Meles Morreni^ the Lutra antiqua, the Sciurus priscus, the 

 Arctomys primigenia, the Myoxus fossilis, the Sus priscus, etc. 

 Some of these are probably identical with living species. By new 

 researches we shall find that some of these are truly extinct. 



But, aside from these difficulties and doubts, a certain number of 

 species have certainly disappeared, which I will briefly enumerate. 



In the family of Bears I consider as lost the great Cavern Bear 

 (Ursus spelceus). Their bones characterize well the deposits called 

 Diluvian, or the formations more ancient than the last period of our 

 globe. The Ursus prisons is more doubtful, and is probably identical 

 with our black bear. The Hyenas appear to have been represented 



