248 DESCRIPTION OF THE MUSEUM. 



world, beginning with the most simple, arid 

 ending with the most complicated (i). 



(i) Almost all the animals which we see here existed before the last 

 revolution which changed the surface of the globe. The greater num- 

 ber of them are lost species ; several cannot even be traced to any of 

 the genera we now know; they belong to different periods, and the 

 more distant the period the less they resemble those which now exist. 



The presence of fossil organized bodies, conjoined with the super- 

 position of heterogeneous layers, demonstrate the relative age of forma- 

 tions, and give positive notions, independent of all system, on the 

 theory of the earth, and the changes which successively took place on 

 its surface. There are no organized bodies in primitive formations ; 

 madrepores, shells, some Crustacea? and fishes, appear first in the tran- 

 sition formations'; other shells, fishes, and some reptiles belong to a 

 second period of formation ; new families of shells, fishes, and reptiles 

 occur in the third period, they are accompanied by reptiles, birds and 

 mammalia of lost genera. The species of mammalia resembling those 

 which are living, as elephants, rhinoceros, and bears are only found in 

 alluvial formations caused by the last deluge. 



The prodigious number of remains of the same species of animals, 

 their arrangement*in beds, and the preservation of certain shells, lead 

 us to believe that several ages have elapsed between the several 

 revolutions. 



We do not find human bones in any of the formations we have men- 

 tioned, which does not prove that man did not exist upon the earth at 

 the time of the last catastrophe, which gave the continents their actual 

 form, but that he did not inhabit the places which were swallowed up 

 by the waters, or that his foresight and industry furnished him with the 

 means of retreating elsewhere. 



It is at the end of the last series, and only in alluvial formations, that 

 some species appear analogous to our domestic animals, such as the 

 ox, horse, and rabbit. 



It is remarkable that the fossil vegetables, whose species can be 

 determined, appear to belong to genera and even families which are 

 no longer found in our climates. Thus we see trunks of palm-trees in 

 the neighbourhood of Paris, and trunks of arborescent ferns in the 

 ancient coalpits of northern countries. 



