248 ' On Arctic Fossil Plants. 



continuance ! Well, then, either the arctic plants of the ancient 

 world were organized in a manner different from our present 

 equatorial plants, or they were subjected to similar physical 

 conditions. They could not have existed without one or other 

 of these alternatives. Their fate would have been the same as 

 that which is experienced now-a-days by a plant of a warm cli- 

 mate when it is exposed to cold, to prolonged darkness, or to 

 excessive humidity : it dies, and revives no more. But the 

 former alternative is false, for observation has demonstrated the 

 close analogy of these ancient species with our present equatorial 

 plants. There remains, therefore, only the second alternative, 

 that they were really subjected to similar conditions as it regards 

 heat, light, &c. So far as heat is concerned, the similarity of 

 the ancient polar regions is not disputed, because every one ad- 

 mits the necessity of a certain temperature for analogous plants ; 

 but is it not necessary to make the same concession respecting 

 light, which is of as much consequence to vegetables as tempera- 

 ture itself.'' 



I leave it to the natural philosopher to reconcile the pheno- 

 mena which I think we must necessarily admit, with the known 

 laws of our sphere ; namely, that a more uniform and stronger 

 light was at one time shed over the polar regions. I do not 

 mean now to contend for the hypothesis of a change in the in- 

 clination of the terrestrial axis, but only for the fact that light 

 was then otherwise distributed. Perhaps it may one day be dis- 

 covered, that terrestrial magnetism and the high temperature of 

 the globe produced formerly a light which now is unknov/n ; or 

 possibly it may be discovered that there was a time when the 

 aurorae boreales were much more frequent and intense than they 

 at present are ; but this is nothing more than mere hypothesis. 

 What, however, appears to be an incontrovertible fact is this, 

 that the fossil vegetables of Baffin's Bay were formerly under the 

 influence of a different light than are those which vegetate in that 

 region at the present day. 



