450 RECENT ADVANCES IN GEOLOGY. 
seek to set forth what others have accomplished, rather than 
to advance original views. 
. It will be found that, throughout all time, since the earth 
became fitted for the habitation of organic life, that there 
have been great cycles of heat and cold, and that these 
cycles have exercised a marked influence in the modification 
of all terrestrial forms. To traverse the whole ground, 
would employ too much time ; and I shall, therefore, restrict 
myself to the changes which barely antedate the Human. 
Epoch. 
We know that the Tertiary Age, so far, at least, as re- 
lated to the northern hemisphere, was characterized by a - 
warm and equable climate, extending even to the Polar Sea. 
Where now blooms the Andromeda close by banks of per- 
petual snow, at that time grew a luxuriant forest vegetation. 
McClure’s sledging party gathered fragments of fossil wood, 
acorns, and fir cones in the interior of Banks’s Land, far 
within the limits of the Arctie Circle. As high as latitude 
709 N. in Greenland, large forests lie prostrate and encased 
inice. At Disco bta the northern verge of European 
settlement, the strata are full of the trunks, balo leaves, 
and even the seeds and fruit-cones of trees, comprising firs, 
sequoias, elms, magnolias, and laurels, —a vegetation char- 
acteristic of the Miocene Period of Central Europe. Pro- 
fessor Heer particularly notices the Sequoia Langsdorfii, 
which is very closely allied to the Sequoia sempervirens of 
the Coast Range of California. 
Spitzbergen was clothed with a forest vegetation equally 
luxuriant, amongst which the Swedish naturalists recognize 
. the swamp-cypress ( Taxodium dubium) in a fossilized state, 
at Bell's Sound (769 N.), and the plantain and linden in 
King's Bay (78° and 799 N.). The same Sequoia was ob- 
served by Sir John Richardson within the Arctic Circle west 
of MacKenzie River. The lignite beds of Iceland have 
yielded to the botanists, Steenstrup and Heer, fifteen arbor- 
escent forms identical with the Miocene plants of Europe. 
