438 Darwin, and after Darwin. 
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 diffi- 
culties 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 in- 
stance, 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 differ- 
entiated 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 op- 
ponents of this theory can prove their negative by furnishing 
evidence to the contrary. And altlough 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 numberless other cases 
where the geological record does testify to connecting links in 
amost satisfactory manner. For in view of this consideration 
