Prof. Pictet on the Diluvial Epoch. 369 



The diluvial formation is commonly regarded as separated 

 from the modern epoch by characters as decided as those which 

 distinguish the three divisions of the tertiary period. The 

 naturalists who believe absolutely in the peculiarity of the 

 species of the different formations (and, for my own part, I am 

 of opinion that every thing tends to shew that this law is to 

 be considered as demonstrated) think that the order of events 

 was the same in the diluvial epoch as in the others ; that is to 

 say, that at the end of that period all the species became ex- 

 tinct, and that a new creation repeopled the earth at the com- 

 mencement of the modern epoch. 



The study of the facts does not appear to me to justify this 

 conclusion ; and, on the contrary, I think that the diluvial 

 epoch ought to be united with the modern epoch. I believe 

 that there was no new creation, and no interruption of organic 

 life, between the time when the bones of bears were buried in 

 caverns and the present period. Let me, in a few words, ad- 

 duce my reasons for taking this view of the subject, and then 

 point out what I imagine actually occurred. 



The first proof I shall give is derived from the study of the 

 arenaceous deposits in the neighbourhood of Geneva. These 

 deposits have been very properly divided into two portions by 

 M. Necker, — the upper, termed diluvien cataclystique, and con- 

 taining erratic blocks, rolled pebbles, and sand, irregularly 

 stratified ; and the lower, or alluvion ancienne, comj)osed of 

 pebbles, more equal in size, and more regularly arranged in 

 beds, so that we may suppose that they were deposited by a 

 more gentle and more tranquil agent than that by which the 

 upper member was formed. 



This ancient alluvium covers all the bottom of the valley 

 without ever reaching the summit of the acclivities of the 

 Molasse : it could not have been deposited except vmder cir- 

 cumstances very different from those existing at the present 

 day, and it has altogether the characters of the deposits of the 

 diluvial epoch. 



Now, in these ancient alluvial deposits, bones are found 

 which prove that our valley was inhabited at that epoch by 

 species of maxninaWa. perfectly identical with those which now 

 live there. We can detect in these bones no difference o1 



VOL. XXXIX. NO. LXXVIII. — OCTOBEU 1845. 2 A 



