When such varieties returned to their
ancient homes, as they would differ from their former state in a nearly
uniform, though perhaps extremely slight degree, and as they would be found
embedded in slightly different sub-stages of the same formation, they
would, according to the principles followed by many palaeontologists, be
ranked as new and distinct species.
If then there be some degree of truth in these remarks, we have no right to
expect to find, in our geological formations, an infinite number of those
fine transitional forms, which, on our theory, have connected all the past
and present species of the same group into one long and branching chain of
life. We ought only to look for a few links, and such assuredly we do
find--some more distantly, some more closely, related to each other; and
these links, let them be ever so close, if found in different stages of the
same formation, would, by many palaeontologists, be ranked as distinct
species. But I do not pretend that I should ever have suspected how poor
was the record in the best preserved geological sections, had not the
absence of innumerable transitional links between the species which lived
at the commencement and close of each formation, pressed so hardly on my
theory.
ON THE SUDDEN APPEARANCE OF WHOLE GROUPS OF ALLIED SPECIES.
The abrupt manner in which whole groups of species suddenly appear in
certain formations, has been urged by several palaeontologists--for
instance, by Agassiz, Pictet, and Sedgwick, as a fatal objection to the
belief in the transmutation of species.
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