26o [Proc. B. N. F. C, 



We may take those of Greenland, which are the best known 

 and most extensive, as the type, fori believe that all that applies 

 to them, applies no less to the fossil floras of other Arctic lands. 



Heer, we have seen, has determined all the known fossil 

 dicotyledonous floras from all lands within at least 200 geogra- 

 phical miles of the Pole to be either Cretaceous or Miocene. 

 The determination of the age of the Miocene plants of Green- 

 land (lat. 70°) rests upon the supposed identity of some 25 per 

 cent, of them with other supposed Miocene plants occurring in 

 latitudes 23 or 24 degrees to the south (lat. 46° and 47°). Suppos- 

 ing that the age of the more southern plant beds were accurately 

 known, and that the identifications were correct, neither of 

 which points could for one moment be conceded, even this 

 would not prove them to be of the same age ; but rather the 

 contrary, for it would be impossible for floras so much alike and 

 so similar in habit to those of the present day, to grow simul- 

 taneously at, or not far removed from the same level, in such 

 widely different latitudes. We must recollect that these plants 

 are many of them specifically identical with, and nearly all of 

 them closely related to living plants, so that we are bound to 

 infer similarity of habit. The hypothesis, that because floras 

 from widely different latitudes are similarly composed they must 

 have been contemporaneous, would demand, if applied to the 

 existing plant-world, a nearly identical flora growing simultan- 

 eously in Lombardy and Iceland, or Florida and Newfoundland. 

 The living representatives of the fossils, for the most part leafy 

 forest trees, could never have had such a range of latitude, unless 

 stationed on very high land in the south ; but this has never 

 been suggested in the case of the central European Miocene, 

 and is opposed to the conditions under which they were 

 imbedded. The fallacy of this argument is, I trust, apparent. 



We have next the extreme improbability that the plants of 

 the Eocene, a far more important formation than the Miocene, 

 would have been alone overlooked in a series of deposits of 

 immense extent and thickness, abounding in plants, and con- 

 tinuously forming from the Cretaceous to the Upper Miocene. 



