Comparison with 1859 |
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character between the forms of life above and below. We must, however, allow for the entire extinction of some preceding forms, and
for the coming in of quite for the coming in of quite 1859 |
in any one region for the immigration of 1860 1861 1866 1869 1872 |
new forms
by immigration, by immigration, 1859 |
from other regions, 1860 1861 1866 1869 1872 |
and for a large amount of modification,
during the long and blank intervals between the successive formations. Subject to these allowances, the fauna of each geological period undoubtedly is intermediate in character, between the preceding and succeeding faunas. I need give only one instance, namely, the manner in which the fossils of the Devonian system, when this system was first discovered, were at once recognised by palæontologists as intermediate in character between those of the overlying carboniferous, and underlying Silurian system. But each fauna is not necessarily exactly intermediate, as unequal intervals of time have elapsed between consecutive formations. |
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It is no real objection to the truth of the statement,
that the fauna of each period as a whole is nearly intermediate in character between the preceding and succeeding faunas, that certain genera offer exceptions to the rule. For instance, mastodons
and elephants, when arranged by Dr. Falconer in two series, first
according to their mutual affinities
and then
according to their periods of existence,
do not accord in arrangement. The species extreme in character are not the oldest,
or the most recent; nor are those which are intermediate in character, intermediate in age. But supposing for an instant, in this and other such cases, that the record of the first appearance and disappearance of the species was perfect,
we have no reason to believe that forms successively produced necessarily endure for corresponding lengths of time:
a
very ancient form might
occasionally last
much longer than a form elsewhere
subsequently produced, especially in the case of
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character between the forms of life above and below. We must, however, allow for the entire extinction of some preceding forms, and
in any one region for the immigration of in any one region for the immigration of 1860 1861 1866 1869 1872 |
for the coming in of quite 1859 |
new forms
from other regions, from other regions, 1860 1861 1866 1869 1872 |
by immigration, 1859 |
and for a large amount of
modification, modification, 1859 1860 1861 1866 1869 | modification 1872 |
during the long and blank intervals between the successive formations. Subject to these allowances, the fauna of each geological period undoubtedly is intermediate in character, between the preceding and succeeding faunas. I need give only one instance, namely, the manner in which the fossils of the Devonian system, when this system was first discovered, were at once recognised by palæontologists as intermediate in character between those of the overlying carboniferous, and underlying Silurian
system. system. 1859 1860 1861 1866 1869 | systems. 1872 |
But each fauna is not necessarily exactly intermediate, as unequal intervals of time have elapsed between consecutive formations. |
|
It is no real objection to the truth of the
statement, statement, 1859 1860 1861 | statement 1866 1869 1872 |
that the fauna of each period as a whole is nearly intermediate in character between the preceding and succeeding faunas, that certain genera offer exceptions to the rule. For instance,
mastodons mastodons 1859 1860 1861 1866 1869 |
the species of mastodons 1872 |
and elephants, when arranged by Dr. Falconer in two
series, first series, first 1859 1860 1861 1866 1869 |
series,— in the first place 1872 |
according to their mutual
affinities affinities 1859 1860 1861 1866 1869 | affinities, 1872 |
and
then then 1859 1860 1861 1866 1869 |
in the second place 1872 |
according to their periods of
existence, existence, 1859 1860 1861 1866 1869 | existence,— 1872 |
do not accord in arrangement. The species extreme in character are not the
oldest, oldest, 1859 1860 1861 | oldest 1866 1869 1872 |
or the most recent; nor are those which are intermediate in character, intermediate in age. But supposing for an instant, in this and other such cases, that the record of the first appearance and disappearance of the species was
perfect, perfect, 1859 1860 1861 1866 1869 |
complete, which is far from the case, 1872 |
we have no reason to believe that forms successively produced necessarily endure for corresponding lengths of
time: time: 1859 1860 1861 1866 1869 | time. 1872 |
a a 1859 1860 1861 1866 1869 | A 1872 |
very ancient form
might might 1859 1860 1861 1866 1869 | may 1872 |
occasionally
last last 1859 1860 1861 1866 1869 | have lasted 1872 |
much longer than a form
elsewhere elsewhere 1859 1860 1861 1866 1872 | else-where 1869 |
subsequently produced, especially in the case of
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