260 Professor Pictet on the Distribution of Fossils. 



faunas. It may often be interesting to know whether these 

 species more or less resemble such as have preceded or fol- 

 lowed them. 



These principles established, the question becomes simpli- 

 fied, and its solution depends entirely on the examination of 

 facts, under the guidance of systems of zoology properly so 

 called. It would then seem that nothing remains but to 

 compare the lists of the fossils of each formation, as they are 

 established by palaeontologists, in order to observe if the same 

 names occur there. Unfortunately these lists, often drawn 

 up in haste, and sometimes by superficial observers, or those 

 who have little acquaintance with zoology, are not always 

 such as to deserve confidence, and the greater part of them 

 are full of errors. The result which the comparison of them 

 would furnish, if we were to receive them as correct, would 

 be, that numerous species are found in many formations ; but 

 the more we study fossils, the more we disclaim these al- 

 leged identities ; and I have no doubt that, as science ad- 

 vances, we shall discover that it is only in consequence of er- 

 roneous assimilations that the same names have been in- 

 serted in catalogues of the fossils of different formations.* 

 The actual state of the science does not, perhaps, warrant us 

 to affirm it, but all probability is in favour of the specialty 

 of fossils. All investigations carefully conducted by compe- 

 tent zoologists, and with that precision which is pre-eminently 

 requisite in palaeontology, have almost invariably led to the 

 conclusion that fossils are different in every formation. The 

 most eminent palaeontologists are now agreed on this funda- 

 mental fact, and I entertain the firm conviction that we may 

 confidently expect its confirmation with the progress of time. 

 It is, moreover, natural that the earliest observers should 

 have been at first more struck with the analogies than the 

 differences ; a superficial examination shews the former more 

 speedily, while the second demands more labour. The same 

 thing has taken place with regard to living animals, ancient 



* We shall afterwards have occasion, in the particular history of fos- 

 sils, to draw frequent attention to species which have been erroneously 

 considered as identical in different formations. 



