Paleontology. 161 
fossil state, or of our finding them even if they 
have been. Therefore, if the theory of evolution is 
true, we ought not to expect from the geological 
record a full history of specific changes in any but 
at most a comparatively small number of instances, 
where local circumstances happen to have been 
favourable for the writing and preservation of such a 
history. But we might reasonably expect to find a 
general concurrence of geological testimony to the 
larger fact—namely, of there having been throughout 
all geological time a uniform progression as regards 
the larger taxonomic divisions. And, as I will next 
procecd to show, this is, in a general way, what we do 
find, although not altogether without some important 
exceptions, with which I shall deal in an Appendix. 
There is no positive proof against the theory of 
descent to be drawn from a study of palxontology, or 
proof of the presence of any kind of fossils in strata 
where the fact of their presence is incompatible with 
the theory of evolution. On the other hand, there is 
an enormous body of uniform evidence to prove two 
general facts of the highest importance in the present 
connexion. The first of these general facts is, that an 
increase in the diversity of types both of plants and 
animals has been constant and progressive from the 
earlest to the latest times, as we should anticipate that 
it must have been on the theory of descent in ever- 
ramifying lines of pedigree. And the second general 
fact is, that through all these branching lines of ever- 
multiplying types, from the first appearance of each 
of them to their latest known conditions, there is 
overwhelming evidence of one great law of organic 
nature—the law of gradual advance from the general 
* M 
