There seems to
have been no culminating point in the series when the uplifted
earth shivered in a mantle of ice and snow. Yet I propose to
retain for this period--beginning early in the Cretaceous (Chalk)
period and extending into the Tertiary--the name of the
Cretaceous Revolution. I drew a fanciful parallel between the
three revolutions which have quickened the earth since the
sluggish days of the Coal-forest and the three revolutionary
movements which have changed the life of modern Europe. It will
be remembered that, whereas the first of these European
revolutions was a sharp and massive upheaval, the second
consisted in a more scattered and irregular series of
disturbances, spread over the fourth and fifth decades of the
nineteenth century; but they amounted, in effect, to a
revolution.
So it is with the Cretaceous Revolution. In effect it corresponds
very closely to the Permian Revolution. On the physical side it
includes a very considerable rise of the land over the greater
part of the globe, and the formation of lofty chains of
mountains; on the botanical side it means the reduction of the
rich Mesozoic flora to a relatively insignificant population, and
the appearance and triumphant spread of the flowering plants, on
the zoological side it witnesses the complete extinction of the
Ammonites, Deinosaurs, and Pterosaurs, an immense reduction of
the reptile world generally, and a victorious expansion of the
higher insects, birds, and mammals; on the climatic side it
provides the first definite evidence of cold zones of the earth
and cold seasons of the year, and seems to represent a long, if
irregular, period of comparative cold.
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