C\iv\er as a Naturalist, 351 



must have appeared before reptiles, and the latter before mam- 

 miferous animals. 



The species which anciently inhabited the earth have been 

 destroyed and replaced by others, and the present race is per- 

 haps the fourth. 



Geology thus has a guide through the obscure labyrinths 

 which it is obliged to trace, and a new means of determining 

 the nature of deposits, which often cannot be attained by che- 

 mical analysis, and by the order of superposition. 



Besides the general facts which naturally arose from these 

 discoveries, and which M. Cuvier has discussed in the prelimi- 

 nary discourse to his work, with that power and logical acumen 

 which were peculiar to him, science speedily obtained positive 

 results of the greatest importance ; for, scarcely had this geolo- 

 gical guide been detected, than it led its discoverer to perceive 

 that the stratified deposits of the crust of the globe were divi- 

 sible into two classes, one formed in fresh water, and the other 

 in the water of the sea. This distinction, which could only be 

 made by means of zoology, has demonstrated a fact not less 

 curious, that many parts of the surface of our earth have been 

 covered alternately by the sea and by fresh waters. 



All that we have said of the cabinet of anatomy, we might 

 here repeat regarding the immense collection of fossil bones 

 which he collected, and generously deposited in the museum. 

 He did even more than collect and describe them ; with the in- 

 tention of affording even to the most incredulous an opportuni- 

 ty to feel and believe, he caused models of the principal pieces 

 to be sent to different cabinets throughout Europe. This plan 

 being promptly imitated, has already produced a kind of com- 

 mercial exchange, extremely beneficial to science, and which, 

 there can be little doubt, will daily continue to extend. 



An important problem now presented itself for solution. 

 Since remains of our present animals are nowhere to be found, 

 has man been recently placed on the earth, or rather was he con- 

 temporaneous with the destroyed mammifera, and did he escape 

 destruction by his numbers and superior intelligence ? Accord- 

 ing to M. Cuvier, geology proclaims that man is new, at least 

 on our present continents. He declares that in no regular de- 

 posits are human bones to be met with— all those formerly re- 



Aa2 



