, which evidently formed the first stage of
plant-life on the globe.]
Now, as a matter of fact, there was no one long (or short) period
during which the whole of this command was realized, _before_ the next
creative act occurred.
At first _algae_ and low forms of vegetable life appeared; and doubtless
we have lost myriads upon myriads of such lower forms of plant-life in
the early strata, because such forms were ill calculated for
fossil-preservation, owing to the absence of woody fibre, silicious
casing, or hard fruit or seed vessels. But when we first have a marked
accumulation of specialized plant-life in the coal measures (Upper
Carboniferous), it is still only of cryptogams--ferns and great club
mosses. A beginning of true seed-bearing plants (Gymnosperm exogens) had
been made with the _conifers_ of the Devonian strata; but true
_grasses_, and the other orders of phanerogamic plants and arboreous
vegetation, do not appear till the tertiary rocks were deposited, very
long after the age of fish and great reptiles had culminated, and the
inauguration of the bird age and the mammalian age had taken place.
Looking only to the abundant, prominent, and characteristic life-forms
of the several strata, it could certainly be said that the period
when the _water_ actually brought forth a vast mass of its
life-forms--corals, sertularias, crustaceans, and fish of the lower
orders--must have _preceded_ (not followed) the time when the earth
produced vegetation of all kinds, and further that it must have come
after the appearance of scorpions and some land insects.
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