SUCCESSION OF FORMS 43 



yet at any one geological level the species, the lines of 

 descent, are all distinct from one another. 1 



Cuvier recognised very clearly that there is a succession 

 of forms in time, and that on the whole the most .primitive 

 forms are the earliest to appear. Mammals are later than 

 reptiles, and fishes appear earlier than either. As Deperet 

 puts it, " Cuvier not only demonstrated the presence in the 

 sedimentary strata of a series of terrestrial faunas super- 

 imposed and distinct, but he was the first to express, and that 

 very clearly, the idea of the gradual increase in complexity 

 of these faunas from the oldest to the most recent " (p. 10). 



He did not believe that the fauna of one epoch was 

 transformed into the fauna of the next. He explained the 

 disappearance of the one by the hypothesis of sudden 

 catastrophes, and the appearance of the next by the 

 hypothesis of immigration. He nowhere advanced the 

 hypothesis of successive new creations. " For the rest, when 

 I maintain that the stony layers contain the bones of 

 several genera and the earthy layers those of several species 

 which no longer exist, I do not mean that a new creation has 

 been necessary to produce the existing species, I merely say 

 that they did not exist in the same localities and must have 

 come thither from elsewhere." It was left to d'Orbigny to 

 teach the doctrine of successive creations, of which he 

 distinguished twenty-seven (Cours eleinentaire de palaeontologie 

 stratigraphique, 1 849). 



Cuvier, however, can hardly have believed that all species 

 were present at the beginning, since he does admit a 

 progression of forms. Probably he had no theory on 

 the subject, for theories without facts had little interest 

 for him. At any rate it is a mistake to think that Cuvier 

 was a supporter of the theological doctrine of special 

 creation. His philosophy of Nature was mechanistic, and 

 he dedicated his Recherc/ics snr les Ossemeus Fossiles to his 

 friend Laplace. He admitted the idea of evolution at least 

 so far as to conceive of a development of man from a savage 



1 See C. Deperet, Les transformations dit Monde animal, Paris, 1907, 

 and G. Steinmann, Die geologischen Grundlagen der Abstammungslehre^ 

 Leipzig, 1908. 



2 Recherches, i., p. Si. 



