420 THE DISTRIBUTION OF ANIMALS AND PLANTS 



commencing with Paleotheriuin. The serious complications 

 resulting from such admissions are evident, but Vogt deserves 

 credit for faith and consistency beyond those of his teachers. 



With reference to the actual distribution of species, the 

 question of time becomes most important when applied to^ 

 the Glacial period, since it is obvious that much of the pre- 

 sent distribution must have been caused, or greatly modified, 

 by that event. The astronomical theory would place the 

 close of the Glacial age as far back as 70,000 or 80,000 years 

 ago. But we have already seen in the chapter on that period 

 that geological facts bring its close to only from 10,000 to 

 7,000 years before our time. If we adopt the shorter esti- 

 mates afforded by these facts, it will follow that the submer- 

 gences and emergences of land in the Glacial ages were more 

 rapid than has hitherto been supposed, and that this would 

 react on our estimate of time by giving facilities for more 

 rapid denudation and deposition. Such results would greatly 

 shorten the duration assignal;le to the human period. They 

 would render it less remarkable that no new species of animals 

 seem to have been introduced since the Glacial age, that many 

 insular faunas belong to far earlier times, and that no changes 

 even leading to the production of well-marked varieties have 

 occurred in the post-glacial or modern age. 



In conclusion, does all this array of fact and reasoning 

 bring us any nearer to the comprehension of that " mystery of 

 mysteries," the origin and succession of life ? It certainly does 

 not enable us to point to any species, and to say precisely here, 

 at this time and thus it orginated. If we adopt the theory 

 of evolution, the facts seem to restrict us to that form of it 

 which admits paroxysmal or intermittent introduction of 

 species, depending on the concurrence of conditions favourable 

 to the action of the power, whatever it may be, which pro- 

 duces new organisms. Nor is there anything in the facts of 

 distribution to invalidate the belief in creation, according to 



