of the Distrihuion of Arctic Plants, 341 



ing his bold and free movement, but probably arriving at the same 

 goal at length. Indeed, we freely receive the view which Dr. 

 Hooker presents as appropriate to his particular purpose, and as 

 the most useful expression of our knowledge of the relationships 

 of the plants in question, when collocated in reference to the ideas 

 upon which this memoir is based.' 



Among the geological objections to the general conclusions 

 views of Dr. Hooker, we may state the following : 



1. The modern distribution of plants in the arctic regions is 

 plainly related tt) the more or less'^equable temperature, greater 

 moisture or dryness, and varying soil and geological structure, of 

 portions of this area, in connection with the direction of ocean 

 currents, of prevailing winds, atid tbe migrations of animals. 

 When we consider the distribution of arctic plants to the south- 

 ward, and the peculiarities of their position in respect to meri- 

 dians, we have farther to take into account the great post-pliocene 

 subsidence and the distribution of coast lines and ocean currents 

 at that period, as well as the cold climate, which is only one ele- 

 ment, and a subordinate one, in the decision of the question. 



2. The present flora of Scandinavia is related to its varied levels 

 and soils, and to the moderation of its climate by the action of 

 the gulf stream. In the glacial period its level was reduced by 

 several hundreds of feet, and its climate was probably as cold as 

 that of Greenland. Consequently, though the species inhabiting 

 Scandinavia, or many of them, are no doubt ancient, their residence 

 in Scandinavia may be modern, and there are no facts to show 

 which of them resided there before the glacial period began. 



3. The distribution of the sub-fossil shells of the post-pliocene» 

 shows a shore connection between Scandinavia and Greenland, 

 and at the same time a great depression of temperate Europe and 

 America.* That is, there was much arctic land and little in the 

 temperate zone. This geographical arrangement was no doubt, as 

 Sir C. Lyell argues, the actual cause of the cold of the period. It 

 was consequently impossible that plants could migrate southward 

 except as seeds floated over the ocean, because they were cut oflf 

 by wide seas from all southern l^nd. Nor did they so need to 

 migrate, for the cold of the glacial period did not necessarily im- 

 ply extremes fatal to them, even in the arctic regions, though it 

 produced conditions favourable to them in the islands that re- 

 mained far to the southward. 



• See Canadian Naturalist, vol. 5, p. 199. 



