The Earth's Shifting Crust by Charles Hapgood - wire of information

62 EARTH'S SHIFTING CRUST
ample, says that fossil plants are reliable indicators of past
climate (375 : 237~3 8 )-
It may be worth while to review, very briefly, some high
points of the climatic history of the Arctic and sub-Arctic
regions, beginning with one of the oldest periods, the Devonian,
and coming down by degrees to periods nearer our
own. (During this discussion the reader may find it helpful
to refer to the table of geological periods, page 23.)
The Devonian evidence is particularly rich, and includes
both fauna and flora. Dr. Colbert, of the American Museum
of Natural History, has pointed out that the first known
amphibians have been found in this period in eastern Green-
land, near the Arctic Circle, though they must have required
a warm climate (375:256). Many species of reef corals, which
at present require an all-year sea-water temperature of not
less than 68 F. (102:108), have been found in Ellesmere Is-
land, far to the north of the Arctic Circle (399:2). Devonian
tree ferns have been found from southern Russia to Bear
Island, in the Arctic Ocean (177:360). According to Barghoorn,
assemblages of Devonian plants have been found in
the Falkland Islands, where a cold climate now prevails, in
Spitzbergen, and in Ellesmere Island, as well as in Asia and
America (375:240). In view of this, he remarks:
The known distribution of Devonian plants, especially their diversi-
fication in high latitudes, suggests that glacial conditions did not exist
at the poles (375:240).
In the following period, the Carboniferous, we have evi-
dence summed up by Alfred Russel Wallace, co-author, with
Darwin, of the theory of evolution:
In the Carboniferous formation we again meet with plant remains
and beds of true coal in the Arctic regions. Lepidodendrons and
calamites, together with large spreading ferns, are found at Spitz-
bergen, and at Bear Island in the extreme north of Eastern Siberia;
while marine deposits of the same age contain an abundance of large
stony corals (446:202).
In the Permian, following the Carboniferous, Colbert re-
ports a find of fossil reptiles in what is now a bitterly cold