Professor Pictet on the Distribution of Fossils. 265 



The second fact — whicli rests on the comparison of the 

 faunas of the tertiary formations with the actual geographi- 

 cal distribution of animals on the earth — cannot, in my opi- 

 nion, any more than the other, furnish us with very precise 

 results. It must, indeed, be observed that these comparisons 

 are themselves somewhat vague ; and there is nothing to 

 prove that, because two species resemble each other, they 

 could not live but in the same climate. We think it neces- 

 sary to suppose, for example, that the climate of Europe dur- 

 ing the diluvian epoch was like that of India in our own day ; 

 but there is nothing to shew that the antediluvian elephant 

 may not have been satisfied with a less elevated temperature. 

 The long fleece with which this animal was covered, seems to 

 shew that it was organised to support a greater degree of 

 cold thaa could be endured by the Indian elephant. 



Besides, even on the supposition that these facts furnish 

 direct results which cannot be disputed, they are too insu- 

 lated to prove this constant decrease of temperature. Ad- 

 mitting that the commencement of the diluvian epoch was, in 

 Europe, a time of greater heat, and that, during the period 

 of the coal formation, this same continent enjoyed a tempe- 

 rature like that of the tropical regions in the present day, it 

 would remain to be proved that all the intermediate epochs, 

 during which a period elapsed as lengthened as that which 

 separates us from the antediluvian elephant, have undergone 

 a uniform decrease in temperature. But I nowhere find suf- 

 ficient proofs of this. There is nothing to shew that, in the 

 faunas of the cretaceous or Jurassic formations, the tempera- 

 ture has been sensibly difi^erent from what it now is. Pre- 

 cise and positive facts, such as are necessary to produce an 

 enlightened conviction, are everywhere wanting. It is im- 

 possible not to perceive that, in this question, the imagina- 

 tion has outstripped the instruction furnished by Nature. * 



* I believe that what is supposed to give consistency to these opinions, 

 is the connection which has been established between palseontologlcal facts 

 and the increase of temperature as we descend into the crust of the globe. 

 It has been said that the solidification of the earth has commenced at the 

 surface ; that the layer which had been cooled always augmented ; and 

 that, consequently, in the geological epochs, when it was thinner, the 



VOL. XL. NO. LXXX. — APRIL 1846. S 



