,
or into small existing groups which now lie between other large existing
groups. Cases like the foregoing, of which there are many, form steps,
though few and far between, in a series of the kind required by my
theory.

{311} _Origin_, Ed. i. p. 301, vi. p. 440.

{312} _Origin_, Ed. i. p. 329, vi. p. 471.

{313} The structure of the Pachyderm leg was a favourite with the
author. It is discussed in the Essay of 1842, p. 48. In the present
Essay the following sentence in the margin appears to refer to
Pachyderms and Ruminants: "There can be no doubt, if we banish all
fossils, existing groups stand more separate." The following occurs
between the lines "The earliest forms would be such as others could
radiate from."

As I have admitted the high improbability, that if every fossil were
disinterred, they would compose in each of the Divisions of Nature a
perfect series of the kind required; consequently I freely admit, that
if those geologists are in the right who consider the lowest known
formation as contemporaneous with the first appearances of life{314}; or
the several formations as at all closely consecutive; or any one
formation as containing a nearly perfect record of the organisms which
existed during the whole period of its deposition in that quarter of the
globe;--if such propositions are to be accepted, my theory must be
abandoned.

{314} _Origin_, Ed. i. p. 307, vi. p. 448.

If the Palaeozoic system is really contemporaneous with the first
appearance of life, my theory must be abandoned, both inasmuch as it
limits _from shortness of time_ the total number of forms which can have
existed on this world, and because the organisms, as fish, mollusca{315}
and star-fish found in its lower beds, cannot be considered as the
parent forms of all the successive species in these classes. But no one
has yet overturned the arguments of Hutton and Lyell, that the lowest
formations known to us are only those which have escaped being
metamorphosed <illegible>; if we argued from some considerable districts,
we might have supposed that even the Cretaceous system was that in which
life first appeared. From the number of distant points, however, in
which the Silurian system has been found to be the lowest, and not
always metamorphosed, there are some objections to Hutton's and Lyell's
view; but we must not forget that the now existing land forms only 1/5
part of the superfic