174 
Simmons, Remarks about tbe Relations of the Floras etc. 
from the Polar Sea through the openings between the continents. 
If Bering Strait was already tlien a narrow sound, while there 
were wider entrances to the Atlantic, such a distribution of land 
and water must liave made it very much easier for the tertiary 
polar algae to retreat to the latter ocean than to the Pacific, 
which would consequently not get as many citizens from the 
tertiary polar flora as the Atlantic. At first the less hardy algae 
migrated soutliwards and totally left their former homestead, 
then, in the same measure as the glaciation went forward, also 
the arctic forms, which now must have existed, began to wander 
southwards into the upper parts of the oceans, which were gra- 
dually cooled down, until during the maximal glaciation an arc- 
tic flora grew along the coasts far beyond its present limit. 
Here arises the question, if the arctic flora then held not only 
the present temperate region but also its present area besides. 
The opinion of Kj eil man is, that it has never left the Polar 
Sea, as it appears from liis discussion of the liistory of the flora, 
and from the summary (30, p. 61): „The Flora has had its centre 
of development in the Arctic Sea, Its area was more extensive 
during the glacial period than at present. It has been recrui- 
ted in later times by more Southern species.“ 
To me its seems impossible, that the Polar Sea can have 
offered the necessary conditions of life for the greater part of 
its present inhabitants during the maximuni of glaciation. Even 
the coast of Norway, now temperate, then must have been al- 
most or perhaps entirely destitute of Vegetation, because the 
great inlandice formed the entire coastline. The same must have 
been the case with most parts of Greenland and also other 
arctic lands. Along a. glacierfront of such a thickness as it is 
here the question of there can of course not have been any 
Vegetation, the ice protruded to depths where all algae are wan- 
ting. Indeed there must have been places here and there where 
the coast was formed of rocks, but here the seaice made the 
existence of a Vegetation impossible at least in the littoral region. 
Even now the icefoot lies unbroken from year to year in many 
parts of the arctic coasts, and this must have been the rule du- 
rins: the iceage, when the climate was still more unfavorable 
than now. Consequently the littoral Vegetation must have been 
totally extinct in the polar regions during the maximal glaciation. 
For the sub littoral algae the conditions can perhaps have been some- 
what more favorable, at least locally. But even for them it must have 
been extremely difficult to hold the ground. The sea has been iceco- 
vered for most part of the year, in some places perhaps always, 
and even at points, where there has been some open water in 
the summer, they have had to fight against still stronger ene- 
mies than now. AVe see how in the present arctic seas the 
rock-bottom is rubbed and almost polished far down in the sub- 
littoral region by the driftice, and the mud- or gravel-bottom 
ploughed up so that hardly any algae can take stand there. The 
most luxuriant Vegetation is always to be found in the sheltered 
