Geologists think them superfluous. There
is another set of facts to be considered in connection with the
Permian cold.
As we have seen several times, there are periods when, either
owing to the shrinking of the earth or the overloading of the
sea-bottoms, or a combination of the two, the land regains its
lost territory and emerges from the ocean. Mountain chains rise;
new continental surfaces are exposed to the sun and rain. One of
the greatest of these upheavals of the land occurs in the latter
half of the Carboniferous and the Permian. In the middle of the
Carboniferous, when Europe is predominantly a flat, low-lying
land, largely submerged, a chain of mountains begins to rise
across its central part. From Brittany to the east of Saxony the
great ridge runs, and by the end of the Carboniferous it becomes
a chain of lofty mountains (of which fragments remain in the
Vosges, Black Forest, and Hartz mountains), dragging Central
Europe high above the water, and throwing the sea back upon
Russia to the north and the Mediterranean region to the south.
Then the chain of the Ural Mountains begins to rise on the
Russian frontier. By the beginning of the Permian Europe was
higher above the water than it had ever yet been; there was only
a sea in Russia and a southern sea with narrow arms trailing to
the northwest.
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