GENERAL LAWS OF ORIGIN AND MIGRATION. 257 



in Europe, and in the modern epoch forms that would be 

 regarded in Europe as Miocene still exist. Much confu- 

 sion in reasoning as to the geological ages of the fossil floras 

 has arisen from want of attention to this circumstance. 



What we have learned respecting this wonderful his- 

 tory has served strangely to change some of our precon- 

 ceived ideas. We must now be prepared to admit that 

 an Eden can be planted even in Spitzbergen, that there 

 are possibilities in this old earth of ours which its present 

 condition does not reveal to us ; that the present state of 

 the world is by no means the best possible in relation to 

 climate and vegetation ; that there have been and might 

 be again conditions which could convert the ice-clad arc- 

 tic regions into blooming paradises, and which at the 

 same time would moderate the fervent heat of the tropics. 

 We are accustomed to say that nothing is impossible with 

 God ; but how little have we known of the gigantic pos- 

 sibilities which lie hidden under some of the most com- 

 mon of his natural laws ! 



These facts have naturally been made the occasion of 

 speculations as to the spontaneous development of plants 

 by processes of varietal derivation. It would, from this 

 point of view, be a nice question to calculate how many 

 revolutions of climate would suffice to evolve the first land- 

 plant ; what are the chances that such plant would be so 

 dealt with by physical changes as to be preserved and 

 nursed into a meagre flora like that of the Upper Silurian 

 or the Jurassic ; how many transportations to Greenland 

 would suffice to promote such meagre flora into the rich 

 and abundant forests of the Upper Cretaceous, and to 

 people the earth with the exuberant vegetation of the 

 early Tertiary. Such problems we may never be able to 

 solve. Probably they admit of no solution, unless we in- 

 voke the action of an Almighty mind, operating through 

 long ages, and correlating with boundless power and wis- 

 dom all the energies inherent in inorganic and organic 



