EVIDENCES OF EVOLUTION 35 



of a series, e. g. between a high spiral and a 

 flat spiral, is often so striking that no one 

 would hesitate in calling them distinct 

 species. Yet they are connected by a long 

 series of fine gradations. 



Some are surprised that such series are not 

 commoner if Evolution has been the mode of 

 the becoming of things; but they have not 

 adequately understood how great are the 

 odds against the preservation of such records. 

 Only hard parts make good fossils; only cer- 

 tain kinds of deposits make suitable tombs; 

 many rocks have been unmade and re-made 

 several times; these and many other facts 

 enable us to understand 'the imperfection 

 of the geological record.' As Darwin said, 

 we must look at the geological record " as a 

 history of the world imperfectly kept, and 

 written in a changing dialect; of this history 

 we possess the last volume alone, relating 

 only to two or three countries. Of this 

 volume, only here and there a short chapter 

 has been preserved; and of each page, only 

 here and there a few lines.' And again he 

 said: "We shall perhaps best perceive the 

 improbability of our being enabled to connect 

 species by numerous fine intermediate fossil 

 links, by asking ourselves whether, for in- 

 stance, geologists at some future period will 

 be able to prove that our different breeds of 



