Woodward, Woodward, 1859 1860 1861 1872 | Wood-ward, 1866 | Wood- ward, 1869 |
have concluded that the average duration of each formation is twice or thrice as long as the average duration of specific forms. But insuperable difficulties, as it seems to me, prevent us
from coming from coming 1866 1869 1872 | coming 1859 1860 1861 |
to any just conclusion on this head. When we see a species first appearing in the middle of any formation, it would be rash in the extreme to infer that it had not elsewhere previously existed. So again when we find a species disappearing before the
last last 1866 1869 1872 | uppermost 1859 1860 1861 |
layers have been deposited, it would be equally rash to suppose that it then became
....... 1866 1869 1872 | wholly 1859 1860 1861 |
extinct. We forget how small the area of Europe is compared with the rest of the world; nor have the several stages of the same formation throughout Europe been correlated with perfect accuracy. |
We may safely infer that with We may safely infer that with 1872 |
With 1859 1860 1861 1866 1869 |
marine animals of all
kinds kinds 1872 | kinds, 1859 1860 1861 1866 1869 |
there has been there has been 1872 |
we may safely infer 1859 1860 1861 1866 1869 |
a large amount of migration
due to due to 1872 | during 1859 1860 1861 1866 1869 |
climatal and other changes; and when we see a species first appearing in any formation, the probability is that it only then first immigrated into that area. It is
well-known, well-known, 1872 | well known, 1859 1860 1861 1866 1869 |
for instance, that several species appeared
somewhat somewhat 1859 1860 1872 | some-what 1861 1866 1869 |
earlier in the palæozoic beds of North America than in those of Europe; time having apparently been required for their migration from the American to the European seas. In examining the latest deposits
in in 1866 1869 1872 | of 1859 1860 1861 |
various quarters of the world, it has everywhere been noted, that some few still existing species are common in the deposit, but have become extinct in the immediately surrounding sea; or, conversely, that some are now abundant in the neighbouring sea, but are rare or absent in this particular deposit. It is an excellent lesson to reflect on the ascertained amount of migration of the inhabitants of Europe during the
glacial glacial 1861 1866 1869 1872 | Glacial 1859 1860 |
epoch, epoch, 1869 1872 | period, 1859 1860 1861 | period; 1866 |
which forms only a part of one whole geological
period; period; 1859 1861 1866 1869 1872 | period: 1860 |
and likewise to reflect on the
....... 1869 1872 | great 1859 1860 1861 1866 |
changes of level, on the
extreme extreme 1869 1872 | inordinately great 1859 1860 1861 1866 |
change of climate,
and on the great and on the great 1869 1872 |
on the prodigious 1859 1860 1861 1866 |
lapse of time, all included within this same glacial period. Yet it may be doubted
whether, whether, 1866 1869 1872 | whether 1859 1860 1861 |
in any quarter of the world, sedimentary deposits,
including
including
1859 1860 1866 1869 1872 | including 1861 |
fossil
fossil
1859 1860 1866 1869 1872 | fossil 1861 |
remains
,
remains
,
1859 1860 1866 1872 | remains, 1861 |
remains,
1869 |
have gone on accumulating within the same area during the whole of this period. It is not, for instance, probable that sediment was deposited during the whole of the glacial period near the mouth of the Mississippi, within that limit of depth at which marine animals can
best flourish: best flourish: 1869 1872 | flourish; 1859 1860 1861 1866 |
for we know
that that 1869 1872 | what 1859 1860 1861 1866 |
great great 1869 1872 | vast 1859 1860 1861 1866 |
geographical changes occurred in other parts of America during this space of time. When such beds as were deposited in shallow water near the mouth of the Mississippi during some part of the glacial period shall have been upraised, organic remains will probably first appear and disappear at different levels, owing to the
migrations migrations 1869 1872 | migration 1859 1860 1861 1866 |
of species and to geographical changes. And in the distant future, a
geologist, geologist, 1866 1869 1872 | geologist 1859 1860 1861 |
examining
|