470 



THE GEOLOaiST. 



thirty-two thousand. Taking the like sum as representative of a similar increase 

 of species in the vegetable kingdom ; and we obtain then, as a final result, the 

 conclusion that the creative action as exerted in the direct creation of species, 

 commencing in the pre-Silurian period at unity, has been successively and con- 

 tinuously intensified ever since, until now ifc has obtained an intensity sixty-four 



FIRST AJ'PEfiRANCE 



OF MQ.LLUSC R. 



Y 



FiKST Appeabakce Of Life. 



Diaj^rainmatic View of tlto Actual Increase of Species of j\[ollusca, iUustratmo' the increasiBg 

 mU'iisUios of croativo aclioii at the periods stuted, if the theory of the chi^ect creations of 

 Bpoovos bo nduiitt^d. 



[Each Unc of the Tree of Numerical Increase of Specific Forms represents 100 species.] 



ilionsand times greater than when it commenced ; or upwards of twentv-one 

 tlumsamUimcs greater than it was at that point in past time— the Siliman era 

 —to which wc can trace back the records of its action. 



The radiata, tlie vcrtcbrata, or any other class, exhibit the like results 

 wuh tho mollusca, conilrming the impression of the prolificncss of exist- 

 ing species as due to the natural sulD-division by natural trausmutating 



