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4 
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1876.] The Former Climate of the Polar Regions. 357 
Among the ferns, cycadeæ, and conifers of Noursoak peninsula, 
were found a few impressions of a species of the poplar, Populus 
primeva, which formed the only and at the same time the old- 
est known representative of the forest vegetation now prevailing 
in the temperate zone. Nevertheless the vegetation of the arctic 
tracts was already during the Cretaceous period undergoing a 
complete transformation. Evidence of this has been obtained 
from the same locality, Atanekerdluk, on the south side of the 
Noursoak peninsula, from which such magnificent remains of 
arctic vegetation of the Tertiary period had previously been ob- 
tained, from strata at a somewhat higher level. Here, out of 
the talus that has fallen from the lofty fells, some black and 
tolerably easily crumbling strata of shale protrude, among which, 
on careful inspection, impressions of plants may be discovered 
belonging to the Cretaceous formation, not to the lower, but 
the upper portion of it. The vegetation is here quite differ- 
ent. The ferns and cycadez have disappeared, and in their place 
we find deciduous trees and other dicotyledons in astonishing 
variety and forms, among which a species of fig may be men- 
tioned, of which not only the leaves, but also the fruit, have been 
obtained in a fossil state ; two species of magnolia, etc. The 
climate that then prevailed over the whole globe was therefore 
still warm and luxuriant, even if, at least in the arctic regions, 
considerably modified from what it formerly had been, inasmuch 
ae that the flowerless vegetation (which was now beginning to 
die out), as far as we can judge from its present representatives, 
the ferns, required a warm, humid climate, whereas the new 
forms with their luxuriant flowers, which now began to charac- 
terize the vegetable world, required, in order to develop all the 
grandeur of their colors, a clear and sunny sky. The disappear- 
ance of sundry tropical and sub-tropical forms that are met with 
in the older Cretaceous strata has led Heer to the conclusion 
that difference of climate at different latitudes was now begin- 
mng to show itself, and he calls attention to the circumstance 
that this takes place synchronously with the development of the 
dicotyledonous plants in greater variety. ` 
Unhappily, in the arctic regions no fossil remains belonging 
to the Eocene age, which immediately succeeded the Cretaceous 
Period, have hitherto been met with, and we are therefore desti- 
tute of the actual data necessary for ascertaining its climatic 
character, But the next following, or Miocene, age places at 
Sur disposal abundant materials in the magnificent remains of 
