portion of 19
to 12-1/2 the whole of the newer Palaeozoic formations. Lastly, after
giving these examples, Darwin adds the important consideration, that "in
many regions the metamorphic and granitic rocks would be found much more
widely extended than they appear to be, if all the sedimentary beds were
removed which rest unconformably on them, and which could not have
formed part of the original mantle under which they were crystallized."

The above is a brief condensation of the already condensed statement
which Darwin has given of the imperfection of the geological record; but
I think it is enough to show, in a general way, how precarious must be
the nature of any objections to the theory of evolution which are
founded merely upon the silence of palaeontology in cases where, if the
record were anything like complete, we should be entitled to expect from
it some positive information. But, as we have seen in the text,
imperfect though the record be, in as far as it furnishes positive
information at all, this is well-nigh uniformly in favour of the theory;
and therefore, even on grounds of palaeontology alone, it appears to me
that Darwin is much too liberal where he concludes his discussion by
saying,--"Those who believe that the geological record is in any degree
perfect, will undoubtedly at once reject the theory." If in any measure
reasonable, such persons ought rather to examine their title to such a
belief; and even if they disregard the consensus of testimony which is
yielded by all the biological sciences to the theory of evolution, they
ought at least to hold their judgment in suspense until they shall have
not only set against the apparently negative testimony which is yielded
by geology its unquestionably positive testimony, but also well
considered the causes which may--or rather must--have so gravely
impaired the geological record.

However, be this as it may, I will now pass on to consider the
difficulties and objections which have been brought against the theory
on grounds of palaeontology.

These may be classified under four heads. First, the absence of varietal
links between allied species; second, the sudden appearance of whole
groups of species--not only as genera and families, but even sometimes
as orders and classes--without any forms leading up to them; third, the
occurrence of highly organized types at much lower levels of geological
strata than an evolutionist would antecedently expect; and, four