The Edinburgh New Philosophical Journal, Vol. XLIX: April-October 1850Various
Science
The Edinburgh New Philosophical Journal, Vol. XLIX: April-October 1850
Various
Science -- Periodicals
"III. REIGN OF THE ANGIOSPERMS.--The dominating character of this last
transformation of the vegetation of the globe, is the appearance of
Angiospermous dicotyledons, those vegetables which actually constitute
more than three-fourths of the vegetable creation of our epoch, and
which appear to have acquired this predominance from the commencement
of the Tertiary formations. For a long period I was of opinion that
these vegetables did not begin to appear till after the chalk, with
the earliest beds of the Tertiary formations; but more recent
investigation has shewn that beds belonging to the Chalk formation
present some very distinct examples.
"These vegetables appear even at the beginning of the Chalk formation;
for it is certain that many well-determined species exist in the
quadersandstein and planerkalk of Germany, which appear to correspond
to the green sandstone of France, or green sand of English geologists;
although this formation in France and England has never yielded any of
them, but only some examples of Cycadeæ, Coniferæ, and marine plants.
But in southern Sweden, at Kopingue in Scania, some specimens of
dicotyledonous leaves appear associated with a species of Cycadeæ, in
beds which have been referred to the greensand; so that the whole
Chalk formation would appear to constitute a first period in the reign
of the Angiosperms, forming, so to speak, the passage between the
vegetation of the Secondary and that of the Tertiary formations, still
presenting, as the first, a few Cycadeæ, as the following, some
Angiospermous dicotyledons, and thus paving the way to the
considerable development of these vegetables in the succeeding period.
This period is besides characterised by many Coniferæ peculiar to it,
and which appear very distinct from those of the Wealdean formations,
and from those of the Eocene epoch of the Tertiary formations; and
such in particular are the _Cunninghamites_.
"We can therefore distinguish two great periods in the reign of the
Angiosperms:
"_1st_, The Cretaceous period, a kind of period of transition.
"_2dly_, The Tertiary period, presenting all the characters arising
from the predominance of Angiosperms, Dicotyledons, and
Monocotyledons, and divisible into many epochs, the characters of
which will not be well established until we have removed all doubts as
to the agreement of the different local series of the Tertiary
formations.
"V. _Cretaceous Period._--The Cretaceous period, properly so called,
comprehends perhaps many distinct epochs; but the beds where fossil
vegetables have been observed, not having been always classified with
precision in the different subdivisions of this formation, it is
impossible to establish their chronology with certainty. Besides, we
must distinguish an epoch which appears immediately to precede this
formation, and one which follows it, and yet differs from the Eocene
period.
"We are acquainted with fossil vegetables of the Cretaceous period:--
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