| → newer 1861 |
| of the newer 1866 1869 1872 |
|
| → greatly increased in size, if we could remove 1861 |
| seen to be much more widely extended, if 1866 1869 |
| found much more widely extended than they appear to be, if 1872 |
|
| → which 1861 |
| were removed which 1866 1869 1872 |
|
| → at the line of junction have not been metamorphosed, showing that they 1861 |
| OMIT 1866 1869 1872 |
|
| → marking at least sub-stages in the several successive geological epochs, 1861 1866 |
| OMIT 1869 1872 |
|
| → our great deposits rich 1859 1860 1861 1866 |
| the deposits which are richest 1869 1872 |
|
| ←Subtitle not present 1859 1860 1861 On
the
Absence
of
Numerous
Intermediate
Varieties
in
any
one
Single
Formation
.
1866 1869 1872 |
|
the whole
→newer
Palæozoic
In many regions the metamorphic and granitic
would be
→greatly increased in size, if we could remove
all the sedimentary beds
→which
rest unconformably on them, and which
→at the line of junction have not been metamorphosed, showing that they
could not have formed part of the original mantle under which
were crystallized. Hence it is probable that in some parts of the world whole
→marking at least sub-stages in the several successive geological epochs,
have been completely denuded, with not a wreck left behind. |
|
| One remark is here worth a passing notice. During periods of elevation the area of the land and of the adjoining shoal parts of the sea will be increased, and new stations will often be formed;— all circumstances
favourable, as previously explained, for the formation of new varieties and species; but during such periods there will generally be a blank in the geological record. On the other hand, during subsidence, the inhabited area and number of inhabitants will decrease (excepting
on the shores of a continent when first broken up into an archipelago), and consequently during subsidence, though there will be much extinction,
new varieties or species will be formed; and it is during these very periods of subsidence, that
→our great deposits rich
in fossils have been accumulated. Nature may almost be said to have guarded against the frequent discovery of her
or linking forms. →
|
| From
it cannot be doubted that the geological record, viewed as a whole, is extremely imperfect; but if we confine our attention to any one formation, it becomes
difficult to
|
