| → rain-water charged with carbonic acid. 1861 1866 1869 1872 |
| rain-water. 1859 1860 |
|
| → Some 1861 1866 1869 1872 |
| I suspect that but few 1859 1860 |
|
| → kinds of animals 1861 1866 1869 1872 |
| animals 1859 1860 |
|
| → seem to be rarely 1861 1866 1869 1872 |
| are 1859 1860 |
|
| ↑ 1 blocks not present in 1866 1869 1872; present in 1859 1860 1861 |
| The molluscan genus Chiton offers a partially analogous case.
|
|
| → OMIT 1872 |
| from fossil remains 1859 1860 1861 1866 1869 |
|
| → until recently not 1872 |
| not 1859 1860 1861 1866 1869 |
|
| → was 1872 |
| is 1859 1860 1861 1866 |
| until quite recently was 1869 |
|
| → of one species discovered 1860 1861 1866 1869 1872 |
| discovered 1859 |
|
| → and Dr. Dawson in 1860 1861 1866 1869 1872 |
| in 1859 |
|
| → America; but now land-shells have been found in the lias. 1872 |
| America. 1859 |
| America, of which shell several specimens have now been collected. 1860 |
| America, of which shell above a hundred specimens have now been collected. 1861 1866 1869 |
|
| → OMIT 1866 1869 1872 |
| the Supplement to 1859 1860 1861 |
|
|
for ages in an unaltered condition. The remains which do become embedded, if in sand or gravel,
when the beds are
generally be dissolved by the percolation of
→rain-water charged with carbonic acid.
→Some
of the
many
→kinds of animals
which live on the beach between high and low
→seem to be rarely
preserved. For instance, the several species of the Chthamalinæ (a
of sessile cirripedes) coat the rocks all over the world in infinite numbers: they are all strictly littoral, with the exception of a single Mediterranean species, which inhabits deep
and
been found fossil in Sicily, whereas not one other species has hitherto been found in any tertiary
yet it is
known that the genus Chthamalus existed during the
period. ↑
Lastly, many great deposits requiring a vast length of time for their accumulation, are entirely destitute of organic remains, without our being able to assign any reason: one of the most striking instances is that of the Flysch formation, which consists of shale and sandstone, several thousand, occasionally even six thousand feet, in thickness, and extending for at least 300 miles from Vienna to Switzerland; and although this great mass has been most carefully searched, no fossils, except a few vegetable remains, have been found. |
|
| With respect to the terrestrial productions which lived during the Secondary and Palæozoic periods, it is superfluous to state that our evidence
→OMIT
is fragmentary in an extreme degree. For instance,
→until recently not
a land shell
→was
known belonging to either of these vast periods, with
exception
→of one species discovered
by Sir C. Lyell
→and Dr. Dawson in
the carboniferous strata of North
→America; but now land-shells have been found in the lias. In regard to mammiferous remains, a
glance at the historical table published in
→OMIT
will bring home the truth, how accidental and rare is their preservation, far better than pages of detail. Nor is their rarity surprising, when we remember how large a proportion of the bones of tertiary mammals have been discovered either in caves or in lacustrine deposits; and that not a cave or true lacustrine bed is
belonging to the age of our secondary or palæozoic formations. |
|
| But the imperfection in the geological record
results from another and more important cause than any of the foregoing; namely, from the several
being separated from each other by wide intervals of time. This doctrine has been
emphatically admitted by many geologists and palæontologists, who, like E. Forbes , entirely disbelieve in the change of species. When we see the formations tabulated in written works, or when we follow them in nature, it is difficult to avoid believing that they are closely
|
