350 E. J. Pictet on the Diluvian Period. 
those which destroyed one species of ox mentioned by Julius 
Cxsar, 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 popu- 
lation 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 paleontology to pre- 
pore a complete and precise catalogue of these extinct species; 
ut it issuflicient for our purpose to sketch the principal features 
of such a catalogue. 
I am embarrassed in regard to the Alluvial deposits of Au- 
-vergne, which appear to present characters hat ptional 
It is not perfectly demonstrated that the fauna which they en- 
close has all been contemporaneous with the Quaternary deposits 
of the greater part of Europe. There are found many species as 
yet imperfectly known which appear to be extinct and which 
e not been recovered elsewhere. Such is the Lrinaceus 
major, many of the dogs, some polecats, at least three species of 
eer, the wild goats of Roset, &e. It will probably be necessary 
to add to them hereafter; but new investigations appear indis- 
pensable to make the proper additions with certainty. I have 
experienced some doubt in regard to many races or species of 
true Quaternary deposits, indicated as different from those now 
living, but which have been characterized without doubt by their 
orm and not by appreciable organic characters. It appears to 
me quite natural that species at the commencement of the Dilu- 
vian 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 represent 
atives, which, surrounded by hunters, restrained on every side, 
lead a more difficult and precarious life. I do not think it pos- 
sible to give a specific value to slight differences of stature, if 
all the other characters are identical, and therefore I consider as 
doubtful many of those species inserted in the catalogues of pals- 
ontology. Such are the Talpa fossilis, the Meles Morrent, the 
Lutra antiqua, the Sciurus priscus, the Arctomys primigenia, the 
Myoxus fossilis, the Sus priscus, &e. Some of these are probably 
identical with living species. By new researches we shall find 
ct. 
But aside from these difficulties and doubts a certain number 
_ of species have certainly disappeared which I will briefly enu- 
merate. 
In the family of bears I consider as lost the great Cavern 
Bear (Ursus speleus). Their bones characterize well the de- 
osits called Diluvian, or the formations more ancient than the 
t period of our globe. The Ursus priscus is more doubtful 
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