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168）。 To Sir John Herschel in 1836； he wrote； 〃In regard to the origination of new species； I am very glad to find that you think it probable that it may be carried on through the intervention of intermediate causes。 I left this rather to be inferred； not thinking it worth while to offend a certain class of persons by embodying in words what would only be a speculation〃 （Ibid。 page 467）。 He expressed the same views to Whewell in 1837 （Ibid。 Vol。 II。 page 5。）； and to Sedgwick （Ibid。 Vol。 II。 page 36） to whom he says； of 〃the theory； that the creation of new species is going on at the present day〃〃I really entertain it；〃 but 〃I have studiously avoided laying the doctrine down dogmatically as capable of proof〃 （see Huxley in 〃L。L。〃 II。 pages 190…195。））
After pointing out how impossible it would be for a naturalist to prove that a newly DISCOVERED species was really newly CREATED （Mr F。 Darwin has pointed out that his father （like Lyell） often used the term 〃Creation〃 in speaking of the origin of new species （〃L。L。〃 II。 chapter 1。））； Lyell argued that no satisfactory evidence OF THE WAY in which these new forms were created； had as yet been discovered； but that he entertained the hope of a possible solution of the problem being found in the study of the geological record。
It is not difficult； in reading these chapters of Lyell's great work； to realise what an effect they would have on the mind of Darwin； as new facts were collected and fresh observations concerning extinct and recent forms were made in his travels。 We are not surprised to find him writing home； 〃I am become a zealous disciple of Mr Lyell's views； as known in his admirable book。 Geologising in South America； I am tempted to carry parts to a greater extent even than he does。〃 （〃L。L。〃 I。 page 263。）
Lyell's anticipation that the study of the geological record might afford a clue to the discovery of how new species originate was remarkably fulfilled； within a few months； by Darwin's discovery of fossil bones in the red Pampean mud。
It is very true that； as Huxley remarked； Darwin's knowledge of comparative anatomy must have been； at that time； slight； but that he recognised the remarkable resemblances between the extinct and existing mammals of South America is proved beyond all question by a passage in his letter to Henslow； written November 24th； 1832： 〃I have been very lucky with fossil bones； I have fragments of at least six distinct animals。。。I found a large surface of osseous polygonal plates。。。Immediately I saw them I thought they must belong to an enormous armadillo； living species of which genus are so abundant here；〃 and he goes on to say that he has 〃the lower jaw of some large animal which； from the molar teeth； I should think belonged to the Edentata。〃 （〃M。L。〃 I。 pages 11； 12。 See 〃Extracts of Letters addressed to Prof。 Henslow by C。 Darwin〃 （1835）； page 7。）
Having found this important clue； Darwin followed it up with characteristic perseverance。 In his quest for more fossil bones he was indefatigable。 Mr Francis Darwin tells us； 〃I have often heard him speak of the despair with which he had to break off the projecting extremity of a huge； partly excavated bone； when the boat waiting for him would wait no longer。〃 （〃L。L。〃 I。 page 276 （footnote）。） Writing to Haeckel in 1864； Darwin says： 〃I shall never forget my astonishment when I dug out a gigantic piece of armour； like that of the living armadillo。〃 （Haeckel； 〃History of Creation〃； Vol。 I。 page 134； London； 1876。）
In a letter to Henslow in 1834 Darwin says： 〃I have just got scent of some fossil bones。。。what they may be I do not know； but if gold or galloping will get them they shall be mine。〃 （〃M。L。〃 I。 page 15。）
Darwin also showed his sense of the importance of the discovery of these bones by his solicitude about their safe arrival and custody。 From the Falkland Isles （March； 1834）； he writes to Henslow： 〃I have been alarmed by your expression 'cleaning all the bones' as I am afraid the printed numbers will be lost： the reason I am so anxious they should not be； is； that a part were found in a gravel with recent shells； but others in a very different bed。 Now with these latter there were bones of an Agouti； a genus of animals； I believe； peculiar to America； and it would be curious to prove that some one of the genus co…existed with the Megatherium： such and many other points depend on the numbers being carefully preserved。〃 （〃Extracts from Letters etc。〃； pages 13…14。） In the abstract of the notes read to the Geological Society in 1835； we read： 〃In the gravel of Patagonia he （Darwin） also found many bones of the Megatherium and of five or six other species of quadrupeds； among which he has detected the bones of a species of Agouti。 He also met with several examples of the polygonal plates； etc。〃 （〃Proc。 Geol。 Soc。〃 Vol。 II。 pages 211…212。）
Darwin's own recollections entirely bear out the conclusion that he fully recognised； WHILE IN SOUTH AMERICA； the wonderful significance of the resemblances between the extinct and recent mammalian faunas。 He wrote in his 〃Autobiography〃： 〃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 the existing armadillos。〃 （〃L。L。〃 I。 page 82。）
The impression made on Darwin's mind by the discovery of these fossil bones； was doubtless deepened as； in his progress southward from Brazil to Patagonia； he found similar species of Edentate animals everywhere replacing one another among the living forms； while； whenever fossils occurred； they also were seen to belong to the same remarkable group of animals。 （While Darwin was making these observations in South America； a similar generalisation to that at which he arrived was being reached； quite independently and almost simultaneously； with respect to the fossil and recent mammals of Australia。 In the year 1831； Clift gave to Jameson a list of bones occurring in the caves and breccias of Australia； and in publishing this list the latter referred to the fact that the forms belonged to marsupials； similar to those of the existing Australian fauna。 But he also stated that； as a skull had been identified （doubtless erroneously） as having belonged to a hippopotamus； other mammals than marsupials must have spread over the island in late Tertiary times。 It is not necessary to point out that this paper was quite unknown to Darwin while in South America。 Lyell first noticed it in the third edition of his 〃Principles〃； which was published in May； 1834 （see 〃Edinb。 New Phil。 Journ。〃 Vol。 X。 （1831）； pages 394…6； and Lyell's 〃Principles〃 （3rd edition）； Vol。 III。 page 421）。 Darwin referred to this discovery in 1839 （see his 〃Journal〃； page 210。）
That the passage in Darwin's pocket…book for 1837 can only refer to an AWAKENING of Darwin's interest in the subjectprobably resulting from a sight of the bones when they were being unpackedI think there cannot be the smallest doubt； AND WE MAY THEREFORE CONFIDENTLY FIX UPON NOVEMBER； 1832； AS THE DATE AT WHICH DARWIN COMMENCED THAT LONG SERIES OF OBSERVATIONS AND REASONINGS WHICH EVENTUALLY CULMINATED IN THE PREPARATION OF THE 〃ORIGIN OF SPE