| → not 1859 1860 1861 1866 1869 |
| until recently not 1872 |
|
| → is 1859 1860 1861 1866 |
| until quite recently was 1869 |
| was 1872 |
|
| → discovered 1859 |
| of one species discovered 1860 1861 1866 1869 1872 |
|
| → in 1859 |
| and Dr. Dawson in 1860 1861 1866 1869 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 |
| America; but now land-shells have been found in the lias. 1872 |
|
| → the Supplement to 1859 1860 1861 |
| OMIT 1866 1869 1872 |
|
| ↑ 1 blocks not present in 1859 1860; present in 1861 1866 1869 1872 |
| This doctrine has been most
emphatically admitted by many geologists and palæontologists, who, like E. Forbes , entirely disbelieve in the change of species.
|
|
|
is fragmentary in an extreme degree. For instance,
→not
a land shell
→is
known belonging to either of these vast periods, with
exception
→discovered
by Sir C. Lyell
→in
the carboniferous strata of North
→America. In regard to mammiferous remains, a
glance at the historical table published in
→the Supplement to
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. ↑
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 consecutive. But we know, for instance, from Sir R.
great work on Russia, what wide gaps there are in that country between the superimposed formations; so it is in North America, and in many other parts of the world. The most skilful geologist, if his attention had been
to these large territories, would never have suspected
during the periods which were blank and barren in his own country, great piles of sediment, charged with new and peculiar forms of life, had elsewhere been accumulated. And
in each separate territory, hardly
idea can be formed of the length of time which has elapsed between the consecutive formations, we may infer that this could nowhere be ascertained. The frequent
|
