g up to them--notwithstanding that "we know very well the
extensive flora of the underlying Wealden." Moreover, we have all the
three great divisions of the Dicotyledons appearing together, and so
highly differentiated that all the species are referred to existing
genera, with the exception of a very few imperfectly preserved, and
therefore uncertain fragments.

Such being the facts, we may begin by noticing that, even at first
sight, they present different degrees of difficulty. Thus, I cannot see
that there is much difficulty with regard to those in class 2. Only if
we were to take the popular (and very erroneous) view of organic
evolution as a process which is always and everywhere bound to promote
the specialization of organic types--only then ought we to see any real
difficulty in the absence of generalized types preceding these existing
types. Of course we may wonder why still lower down in the geological
series we do not meet with more generalized (or ancestral) types; but
this is the difficulty number 3, which we now proceed to examine.

Concerning the other two difficulties, then, the only possible way of
meeting that as to the absence of any parent forms lower down in the
geological series is by falling back--as in the analogous case of
animals--upon the imperfection of the geological record. Although it is
certainly remarkable that we should not encounter any forms serving to
connect the Dicotyledonous plants of the Chalk with the lower forms of
the underlying Wealden, we must again remember that difficulties thus
depending on the absence of any corroborative record, are by no means
equivalent to what would have arisen in the presence of an adverse
record--such, for instance, as would have been exhibited had the floras
of the Wealden and the Chalk been inverted. But, as the case actually
stands, the mere fact that Dicotyledonous plants, where they first
occur, are found to have been already differentiated into their three
main divisions, is in itself sufficient evidence, on the general theory
of evolution, that there must be a break in the record as hitherto known
between the Wealden and the Chalk. Nor is it easy to see how the
opponents of this theory can prove their negative by furnishing evidence
to the contrary. And although such might justly be deemed an unfair way
of putting the matter, were this the only case where the geological
record is in evidence, it is not so when we remember that there are
numb