OKIGIN OF THE PEOBLEM 11 



D'Orbigny might well feel that the acceptance of 

 twenty-nine complete destructions and complete new 

 creations involved something unworthy of credit. The 

 number was also arbitrarily chosen. If the organisms 

 were always so unchangeable as they appear to be now, 

 then, as a consequence, new creations must be accepted 

 and also the time between each two catastrophes ; 

 since many animal types show, on one and the same 

 geological strata-system, such changes as the theory of 

 ' specific constancy ' cannot admit. 



Why, furthermore, do the new creations so often 

 approach the extinct forms so closely that in many 

 cases the conclusion forces itself upon us, that the im- 

 mediately successive creation must be a simple further 

 development of that immediately preceding ? That is 

 particularly the case when in the immediately preceding 

 creation the organisms already show clear traces of 

 changes in a definite direction, which need be only 

 increased, i.e. further differentiated, in order to perfectly 

 explain the appearance of the immediately succeeding 

 animal and plant creation. Furthermore, the geologist 

 in the meantime had recognized, by more exact observa- 

 tion of the geological formations and denudations of 

 the present day, that the fossil-bearing strata could 

 not have originated catastrophically. At the most 

 such an explanation can only be applied to particular 

 local changes. Lyell especially has the merit of this 

 more natural comprehension of the terrestrial forma- 

 tions (' Principles of Geology/ 1st ed. 1830-38). 



It will, therefore, be willingly conceded that the 



