PRESIDENTIAL ADDRESS. 5 



every living thing upon the earth was destroyed. Furthermore, 

 that the whole earth, at the beginning of each successive period, 

 was stocked anew by special creation, with all its forms of life ; 

 and that these forms were everywhere impressed with the type- 

 characters peculiar to the respective epochs. Even after it 

 became known that in numerous instances species and genera 

 continued their existence from one period to another, it was still 

 held that these were extra-limitary forms, and that their existence 

 did not affect the exclusive character of the types of those 

 animals and plants which were ordained to bear the chrono- 

 logical impress. 



Accepting such a scheme of creation as this, it was natural to 

 suppose that the types of animal and vegetable life which charac- 

 terized each of the geological periods should be universal in its 

 distribution, and strictly confined to the period for which it was 

 specially created. 



Although the doctrine of evolution is now accepted by every 

 working naturalist, this idea of a successive series of narrow 

 chronological horizons of universal extent, each characterized by- 

 its own peculiar types of organic forms, which are everywhere 

 the same, and none of which exist in any other horizon, prevails 

 to almost as great an extent as before. The later naturalists, it is 

 true, based their views of this assumed constancy, not upon the 

 idea of special creation and universal distribution in each period, 

 as their predecessors did, but upon that of a progressive evolu- 

 tion, by distinct and world-wide steps, from pre-existing forms. 

 The views which were held by the older naturalists were the 

 result of a rational deduction from their own premises; but that 

 similar views should be held by the naturalists of to-day is cer- 

 tainly unphilosophical. In accordance with the old views little 

 opportunity was given for the variation of types, because, as they 

 believed, all the species in which those types were expressed 

 were sure to be extinguished at the close of each period, and 

 they were to be succeeded by a newly-created series. 



