THE CARBONIFEROUS AGE.


vegetation, furnished to an unusual degree, the conditions requisite
for the extraction and deposition of iron ore. As these are closely
associated with coal for their reduction, limestone for their fluxing,
and sandstone and fire clays for furnace purposes, the combination
is one of extraordinary industrial advantage.
Life. The new attitude which the land assumed toward the sea
at the close of the Sub-carboniferous period, was accompanied by a
marked change in the character of the life.
Plants. By far the most striking and characteristic expression of
life-progress, was the pronounced development of vegetation during
the Carboniferous age. The great beds of coal, widely scattered
over the continent, indicate a clothing of verdure of more than
tropical luxuriance. We are not left in doubt as to the nature of
these "forests primeval."  Well preserved remains show them to
have been of the same essential character as those of the preceding
Devonian age, differing mainly in their wider range, ampler variety,
and surpassing growth. Not only were there flowerless plants
(Acrogens), but Phenogamous plants were also represented by Gym-
nosperms. Flowers in the ordinary sense were probably entirely
absent. Of the Xcrogens there were Ferns, Eqdseta and Lycopods,
all of which much surpassed their modern representatives. There
were both herbaceous and true ferns, the latter of which attained
great size, single fronds sometimes attaining a length of'six or eight
feet, while the former were probably the most abundant of the coal-
forming plants.
Among Lycopods, Lepidodendrids and Sigillarids were the princi-
pal forms. Both were of great size, reaching at times a height of 60
or 80 feet, placing them in marked contrast to the little Lycopods -
the Ground Pines -of the present day, which, under the most fa-
vorable conditions, rarely reach a height of 4 or 5 feet. The exterior
of their trunks seems to have been composed of dense firm tissue,
while the interior was probably more cellular, as it is often wanting
in erect stumps, while prostrate stems are much compressed. The
exterior was marked by the peculiar and characteristic leafscars,
which, in the Sigillarids, were arranged in vertical rows, and in the
Lepidodendrids in oblique series passing spirally around the trunk.
The Carboniferous Equiseta were sometimes two feet in diameter
and 30 feet high, while their modern representatives -our common
scouring rushes - are but low, slender, herbaceous, plants, though
Mr. Ernst reports a slender species 30 feet high from near Caraccas.
Besides these peculiar forms of vegetation, which grew profusely
in and around the marshes, and which were the principal contrib-


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