RECAPITULATION. 481 



these ancient and utterly unknown epochs of the world^s 

 history. 



I can answer these questions and objections only on the 

 supposition that the geological record is far more imperfect 

 than most geologists believe. The number of specimens in 

 all our museums is absolutely as nothing compared with 

 the countless generations of countless species which have 

 certainly existed. The parent form of any two or more 

 species would not be in all its characters directly interme- 

 diate between its modified offspring, any more than the 

 rock-pigeon is directly intermediate in crop and tail be- 

 tween its descendants, the pouter and fantail pigeons. 

 We should not be able to recognize a species as the parent 

 of another and modified species, if we were to examini7ie 

 the two ever so closely, unless we possessed most of the 

 intermediate links; and owing to the imperfection of the 

 geological recoid, we have no just right to expect to find 

 so many links. If two or three, or even more linking 

 forms were discovered, they would simply be ranked by 

 many naturalists as so many new species, more especially if 

 found in different geological substages, let their dif- 

 ferences be ever so slight. Numerous existing doubtful 

 forms could be named which are probably varieties; but 

 who will pretend that in future ages so many fossil links 

 will be discovered, that naturalists will be able to decide 

 whether or not these doubtful forms ought to be called 

 varieties? Only a small portion of the world has been geo- 

 logically explored. Only organic beings of certain classes 

 can be preserved in a fossil condition, at least in any great 

 number. Many species when once formed never undergo 

 any further change but become extinct without leaving 

 modified descendants; and the periods during which spe- 

 cies have undergone modification, though long as meas- 

 ured by years, have probably been short in comparison 

 with the periods during which they retained the same 

 form. It is the dominant and widely ranging species 

 which vary most frequently and vary most, and varieties 

 are often at first local — both causes rendering the discov- 

 ery of intermediate links in any one formation less likely. 

 Local varieties will not spread into other and distant 

 regions until they are considerably modified and improved; 

 and when they have spread^ ^and are discovered in a geolog- 



