Growing, as Eozoon may be supposed to have done, on the floor of the
ocean, and covering wide patches with more or less irregular masses,
it must have thrown up from its whole surface its pseudopods to seize
whatever floating particles of food the waters carried over it There
is also reason to believe, from the outline of certain specimens, that
it often grew upward in inverted, conical, or club-shaped forms, and
that only the broader patches were penetrated by the tubes or oscula
already mentioned, admitting the sea-water deeply into the substance of
the masses. In this way its growth might be rapid and continuous; but
it does not seem to have possessed the power of growing indefinitely
by new and living layers covering those that had died, in the manner
of some corals. Its life seems to have had a definite termination, and
when that was reached, an entirely new colony had to be commenced.
In this it had more affinity with the Foraminifera, as we now know
them, than with the corals, though practically it had the same power
with the coral polyps of accumulating limestone in the sea-bottom, a
power indeed still possessed by its foraminiferal successors. In the
case of coral limestones, we know that a large proportion of these
consist, not of continuous reefs, but of fragments of coral mixed with
other calcareous organisms, spread usually by waves and currents in
continuous beds over the sea-bottom. In like manner we find in the
limestones containing Eozoon, layers of fragmental matter which shows
in places the characteristic structures, and which evidently represents
the debris swept from the Eozoon masses and reefs by the action of
the waves. With this fragmental matter small rounded organisms to be
noticed in the sequel occur; and while they may be distinct animals
resembling the smaller modern species, they may also be the fry of
Eozoon, or small portions of its acervuline upper surface floated off
in a living state, and possibly capable of living independently and of
founding new colonies.
[Illustration: Fig. 47.--_Slice of Limestone (magnified),_
(_a_) Fragment of Eozoon with canals, (_b_) Fragments of granular
calcite, probably organic, (_c_) Structureless calcite with cleavage
lines (Côte St. Pierre).]
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