110 DARWIMAFA. 



nary period than between the latter and the present 

 time. So far, the Lyellian view is, we suppose, gen- 

 erally concurred in. It is largely admitted that nu- 

 merous tertiary species have continued down into the 

 quaternary, and many of them to the present time. A 

 goodly percentage of the earlier and nearly half of the 

 later tertiary mollusca, according to Des Hayes, Lyell, 

 and, if we mistake not, Bronn, still live. This identifi- 

 cation, however, is now questioned by a naturalist of 

 the very highest authority. But, in its bearings on the 

 new theory, the point here turns not upon absolute 

 identity so much as upon close resemblance. For those 

 who, with Agassiz, doubt the specific identity in any 

 of these cases, and those who say, with Pictet, that 

 "the later tertiary deposits contain in general the 

 debris of species very nearly related to those which 

 still exist, belonging to the same genera, but specifically 

 different," may also agree with Pictet, that the nearly- 

 related species of successive faunas must or may have 

 had " a material connection." But the only material 

 connection that we have an idea of in such a case is a 

 genealogical one. And the supposition of a genealogi- 

 cal connection is surely not unnatural in such cases — 

 is demonstrably the natural one as respects all those 

 tertiary species which experienced naturalists have 

 pronounced to be identical with existing ones, but 

 which others now deem distinct. For to identify the 

 two is the same thing as to conclude the one to be the 

 ancestor of the other. No doubt there are differences 

 between the tertiary and the present individuals, differ- 

 ences equally noticed by both classes of naturalists, but 

 differently estimated. By the one these are deemed 



