160 Darwin, and after Darwin. 
of a positive kind, instead of a mere absence of infor- 
mation of any kind. But if the adverse argument 
reaches only to the extent of maintaining that the 
geological record does not furnish us with so com- 
plete a series of “connecting links’ as we might have 
expected, then, I think, the argument is futile. Even 
in the case of human histories, written with the inten- 
tional purpose of conveying information, it is an 
unsafe thing to infer the non-occurrence of an event 
from a mere silence of the historian—and this espe- 
cially in matters of comparatively small detail, such 
as would correspond (in the present analogy) to the 
occurrence of species and gencra as connecting links. 
And, of course, if the history had only come down to 
us in fragments, no one would attach any importance 
at all to what might have been only the afpareni 
silence of the historian. 
In view, then, of the unfortunate imperfection of 
the geological record per se, as well as of the no less 
unfortunate limitation of our means of reading even 
so much of the record as has come down to us, I 
conclude that this record can only be fairly used 
in two ways. It may fairly be examined for 
positive testimony against the theory of descent, or 
for proof of the presence of organic remains of a 
high order of development in a low level of strata. 
And it may be fairly examined for negative 
testimony, or for the absence of connecting links, 
if the search be confined to the larger taxonomic 
divisions of the fauna and flora of the world. The 
more minute these divisions, the more restricted must 
have been the areas of their origin, and hence the 
less likelihood of their having been preserved in the 
