180 



ISLAND LIFE. 



[part I. 



occurs also in Spitzbergen. The European deposits of the same 

 age closely agree with these in their general character, conifers, 

 cycads, and ferns forming the mass of the vegetation, while 

 exogens are entirely absent, the above-named Greenland poplar 

 being the oldest known dicotyledonous plant. ^ 



If we take these facts as really representing the flora of the 

 period, we shall be forced to conclude that, measured by the 

 change effected in its plants, the lapse of time between the Lower 

 and Upper Cretaceous deposits was far greater than between the 

 Upper Cretaceous and the Miocene — a conclusion quite opposed 

 to the indications afforded by the mollusca and the higher 

 animals of the two periods. It seems probable, therefore, that 

 these Lower Cretaceous plants represent local peculiarities of 

 vegetation such as now sometimes occur in tropical countries. 

 On sandy or coralline islands in the Malay Archipelago there 

 will often be found a vegetation consisting almost wholly of 

 cycads, pandani, and palms, while a few miles off, on moderately 

 elevated land, not a single specimen of either of these families 

 may be seen, but a dense forest of dicotyledonous trees covering 

 the whole country. A lowland vegetation, such as that above 

 described, might be destroyed and its remains preserved by a 

 slight depression, allowing it to be covered up by the detritus of 

 some adjacent river, while not only would the subsidence of 

 high land be a less frequent occurrence, but when it did occur 

 the steep banks would be undermined by the waves, and the 

 trees falling down would be floated away, and would either be 

 cast on some distant shore or slowly decay on the surface or in 

 the depths of the ocean. 



From the remarkable series of facts now briefly summarized, 

 we learn, that whenever plant-remains have been discovered 

 within the Arctic regions, either in Tertiary or Cretaceous 

 deposits, they show that the climate was one capable of support- 

 ing a rich vegetation of trees, shrubs, and herbaceous plants, 

 similar in general character to that which prevailed in the tem- 

 perate zone at the same periods, but showing the influence of 

 a less congenial climate. These deposits belong to at least four 



1 The preceding account is mostly derived from Professor Heer's great 

 work Flora Fossilis Arciica. 



