Vii "THE ORIGIN OF SPECIES " 239 



duce to us a multitude of extinct animals, the 

 existence of which was previously hardly sus- 

 pected; just as if zoologists were to become 

 acquainted with a country, hitherto .unknown, as 

 rich in novel forms of life as Brazil or South 

 Africa once were to Europeans. Indeed, the fossil 

 fauna of the Western Territories of America bid 

 fair to exceed in interest and importance all other 

 known Tertiary deposits put together ; and yet, 

 with the exception of the case of the American 

 tertiaries, these investigations have extended over 

 very limited areas ; and, at Pikermi, were con- 

 fined to an extremely small space. 



Such appear to me to be the chief events in the 

 history of the progress of knowledge during the 

 last twenty years, which account for the changed 

 feeling with which the doctrine of evolution is at 

 present regarded by those who have followed the 

 advance of biological science, in respect of those 

 problems which bear indirectly upon that doc- 

 trine. 



But all this remains mere secondary evidence. 

 It may remove dissent, but it does not compel 

 assent. Primary and direct evidence in favour of 

 evolution can be furnished only by palaeontology. 

 The geological record, so soon as it approaches 

 completeness, must, when properly questioned, 

 yield either an affirmative or a negative answer: 

 if evolution has taken place, there will its mark 



