38 PRELIMINARY INQUIRIES. 



over all Greenland, plants would come first, then insects, and afterwards birds and mammals. Until 

 vegetation clothed the land, animal Ufe must have been absent. There was nothing for it on which 

 to subsist. I have said that the flora is American. This has been amply shown b_y Dr. Hooker 

 in his valuable paper on the distribution of Ai-ctic plants. He has also shown that it is pecidiar in 

 the paucity of the number of its species, compared with other equally Arctic lands ; it con- 

 taining actually fewer species of European plants, than have found their way eastwards from Lapland, 

 by Asia into western and eastern Arctic America.* 



He conceives that this is all explained by Mr. Darwin's hj^othesis, — "First, that the existing 

 Scandinavian flora is of great antiquity ; and that previous to the glacial epoch, it was more imi- 

 foi'mly distributed over the Polar zone than it is now. Secondly, that during the advent of the 

 glacial period the Scandinavian vegetation was driven southwards in every longitude ; and even 

 across the tropics into the south temperate zone. And that on the succeeding warmth of the present 

 epoch, those species that survived both, ascended the mountains of the warmer zones, and also 

 returned northwards accompanied by aborigines of the countries they had invaded during their 

 southern migration."* 



He savs, " If it be granted that the Polar area was once occupied by the Scandina\'ian flora, and 

 that the cold of the glacial epoch did drive this vegetation southwards, it is e\'ideut that the 

 Greenland individuals, from being confined to a peninsida, would be exposed to very difierent 

 conditions to those of the great continents In Greenland many species would, as it wore, be driven 

 into the sea, — that is, exterminated ; and the survivors would be confined to the southern portion 

 of the peninsida. And not being there, brought into competition with other types, there could be no 

 struggle for life amongst their progeny ; and, consequently, no selection of better adapted varieties. 

 On the return of heat these survivors would simply travel northwards unaccompanied by the plants 



of any other covmtry."t 



The first point in the above propositions which I shoidd wish to notice, is the assumed existence 

 of a boreal flora before the commencement of the glacial epoch. This is a point which is always 

 taken for granted. 



The usual conception of the matter is that stated above by Dr. Hooker. Were the question 

 under consideration solely what was the course of action to which these northern types were sub- 

 mitted during and after the glacial epoch, of course the exact period when they first made 

 their appearance would be of little consequence. But it is different with me here. The ques- 

 tion is one of vital importance to my theory, and I cannot afibrd to pass it as a matter of 

 indiflcrence. If the origin of species is in any respect due to change of condition, of life, then 

 at the glacial epoch, if ever, great alterations must have taken place. The southern migra- 

 tion of sjaecies from the north, their subsequent return, and the lingering behind of some on high 

 mountains, no one disputes ; but they are facts belonging to one category, while the original ap- 

 pearance of these northern types are facts belonging to another. It is essential for me to dispute 

 the proposition that these arctic tj'pes existed previous to the glacial epoch. If that were true, my 

 theory woidd be worthless, and I must give it up. But the proposition is not true. Not a single 

 arctic or boreal species of either plant or animal has ever been discovered in any stratum of older date 

 than the glacial epoch. It was the cold of that epoch which produced them all. How soon it was 



* Hooker, in " Trans. Linn. Soc„" xxiii. p. 253. t Hookee, op. cit. pp. 254 and 258. 



