26 CHARLES DARWIN. 



says in the " Autobiography " : — " In July I opened 

 my first note-book for facts in relation to the Origin 

 of Species, about which I had long reflected, and 

 never ceased working for the next twenty years." 

 Furthermore, his pocket-book for 1837 contained 

 the words : — " In July opened first note-book on 

 Transmutation of Species. Had been greatly struck 

 from about the month of previous March" (he was 

 then just over twenty-eight years old) " on character 

 of South American fossils, and species on Galapagos 

 Archipelago. These facts (especially latter) origin of 

 all my views." It is, perhaps, worth while to explain 

 in greater detail the nature of this evidence which 

 appealed so strongly to Darwin's mind. The Edentata 

 (sloths, ant-eaters, armadilloes, etc.) have their metro- 

 polis in South America, and in the later geological 

 formations of this country the skeletons of gigantic 

 extinct animals of the same order (Megatherium, 

 Mylodon, Glyptodon, etc.) are found ; and Darwin 

 was doubtless all the more impressed by discovering 

 such remains for himself. In his " Autobiography " 

 he says: "During the voyage of the Beagle I had 

 been deeply impressed by discovering in the Pampean 

 formation great fossil animals covered with armour 

 like that on existing armadilloes ;...." 



Darwin was thus led to conclude that there was 

 some genetic connection between the animals which 

 have succeeded each other in the same district ; for 

 in a theory of destructive cataclysms, followed by 

 re-creations — or, indeed, in any theory of special 



