There is a considerable
emergence of land at the end of the Jurassic, then a fresh
expansion of the sea, then a great rise of mountains at the end
of the Cretaceous, and so on. We shall find our great
mountain-masses (the Pyrenees, Alps, Himalaya, etc.) rising at
intervals throughout the whole of the Tertiary Era. However, it
suffices for the moment to observe that in the latter part of the
Mesozoic and early part of the Tertiary there were considerable
upheavals of the land in various regions, and that the Mesozoic
Era closed with a very much larger proportion of dry land, and a
much higher relief of the land, than there had been during the
Jurassic period. The series of disturbances was, says Professor
Chamberlin, "greater than any that had occurred since the close
of the Palaeozoic."
From the previous effect of the Permian upheaval, and from the
fact that the living population is now similarly annihilated or
reduced, we should at once expect to find a fresh change in the
climate of the earth. Here, however, our procedure is not so
easy. In the Permian age we had solid proof in the shape of vast
glaciated regions. It is claimed by continental geologists that
certain early Tertiary beds in Bavaria actually prove a similar,
but smaller, glaciation in Europe, but this is disputed.
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