ORIGIN OF THE PROBLEM 9 



and mud, as now happens, he had no conception. 

 As regards the causes of elevation and depression and 

 the significance of volcanic catastrophes the proper 

 understanding failed him entirely. 



But this point of view likewise failed to be per- 

 manently maintained. It was gradually recognized 

 that the separate and sharply denned strata concealed 

 varied fauna and flora in their depths. There must, 

 therefore, have happened several such mighty floods, 

 or catastrophes of other kinds the living world was 

 annihilated repeatedly and arose again as often. Since, 

 however precisely because they often varied greatly 

 from each other no one conceived the thought that 

 the separate successive organic forms might derive 

 their origin from each other by descent, nothing remained 

 but to explain each new organic world by a new creation 

 or successive creation. 



It was not every investigator who understood by 

 c new creation ' a creative act of God. Cuvier, who often 

 used the word, assumed that after the destruction of a 

 defined fauna a new one immigrated from somewhere, 

 so that in this way a new creation, i.e. new creatures, 

 took the place of the extinct ones. Cuvier, however, 

 had no idea of a genetic connection (by descent) 

 between the successive and varied organisms. 1 



Cuvier's pupils, d'Orbigny, d'Archiac and others, 

 carried their master's teaching further : d'Orbigny 3 



1 Compare Chr. Deperet : Die Umbildung der Tierwelt, Stuttgart, 1 909, 10 

 (German translation by R. N. Wegner of the French work, Les Transfor- 

 mations du Monde Anitnal, by Chr. Deperet). 



2 Cours JUlementaire de Palfjeontologie Stratigraphique, II, Paris, 1849, 251. 



