The
vegetarians suffered an appalling reduction of their food; the
carnivores would dwindle in the same proportion. Both types,
again, would suffer from the enormous changes in their physical
surroundings. Vast stretches of marsh, with teeming populations,
were drained, and turned into firm, arid plains or bleak
hill-sides. The area of the Amphibia, for instance, was no less
reduced than their food. The cold, in turn, would exercise a most
formidable selection. Before the Permian period there was not on
the whole earth an animal with a warm-blooded (four-chambered)
heart or a warm coat of fur or feathers; nor was there a single
animal that gave any further care to the eggs it discharged, and
left to the natural warmth of the earth to develop. The
extermination of species in the egg alone must have been
enormous.
It is impossible to convey any just impression of the carnage
which this Permian revolution wrought among the population of the
earth. We can but estimate how many species of animals and plants
were exterminated, and the reader must dimly imagine the myriads
of living things that are comprised in each species. An earlier
American geologist, Professor Le Conte, said that not a single
Carboniferous species crossed the line of the Permian revolution.
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