408 RECAPITULATION. [Chap. XV. 



older species, -why is not every geological formation charged with 

 such links? "Why does not every collection of fossil remains 

 afford plain evidence of the gradation and mutation of the forms 

 of life ? Although geological research has undoubtedly revealed 

 the former existence of many links, bringing numerous forms 

 of life much closer together, it does not yield the infinitely many 

 fine gradations between past and present species required on the 

 theory ; and this is the most obvious of the many objections which 

 may be urged against it. Why, again, do whole groups of allied 

 species appear, though this appearance is often false, to have come 

 in suddenly on the successive geological stages? Although we 

 now know that organic beings appeared on this globe, at a period 

 incalculably remote, long before t the lowest bed of the Cambrian 

 system was deposited, why do we not find beneath this system 

 great piles of strata stored with the remains of the progenitors of 

 the Cambrian fossils ? For on the theory, such strata must some- 

 where have been deposited at these ancient and utterly unknown 

 epochs of the world's history. 



I can answer these questions and objections only on the sup- 

 position 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 intermediate between its modified offspring, any more than 

 the rock-pigeon is directly intermediate in crop and tail between 

 its descendants, the pouter and fantail pigeons. We should not be 

 able to recognise a species as the parent of another and modified 

 species, if we were to examine the two ever so closely, unless we 

 possessed most of the intermediate links ; and owing to the imper- 

 fection of the geological record, 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 geo- 

 logical sub-stages, let their differences be ever so slight. Numerous 

 existing doubtful forms could be named which are probably varie- 

 ties ; but who will pretend that in future ages so many fossil links 

 will be discovered, that naturalists will be able to decide whether 

 Di not these doubtful forms ought to be called varieties ? Only a 

 small portion of the world has been geologically explored. Only 

 organic beings of certain classes can be preserved in a fossil con- 

 dition, at least in any great number. Many species when once 

 formed never undergo any further change but become extinct 



