lO 



NATURE 



[November 2, 191 1 



America were often accompanied by portions of the 

 bony armour, which occur in the same deposit, it is 

 perliaps not surprising that tlie erroneous identification 

 was caught up and repeated in other works on the 

 subject. 



It was not until 1840 that Owen in this country 

 and Lund in Germany established the existence of the 

 several genera of the Glyptodontidaj, and showed that 

 these bony plates really belong to extinct forms allied 

 to the armadilloes. It is therefore very interesting 

 to find that the " untrained " naturalist of twenty-three 

 years of age had divined the real truth on the subject 

 so long before. 



The specimen which excited such intense interest 

 in Darwin's mind was described by him in 1846, after 

 consultation with Owen, as follows : — 



"A double piece, about three feet long and two 

 wide, of the bony armour of a large Dasypoid quad- 

 ruped, with the two sides pressed nearly close 

 together : as the cliff is now rapidly washing away, 

 this fossil was probably lately much more perfect ; 

 from between its doubled-up sides, I extracted the 

 middle and ungueal phalanges, united together, of 

 one of the feet, and likewise a separate phalang : hence 

 one or more of the limbs must have been attached to 

 the dermal case when it was embedded." *^ 



This fine specimen, which w'ould undoubtedly have 

 been of great historical interest, from the effect it 

 produced on the young naturalist's mind, is unfor- 

 tunately no longer in existence. Darwin says " It was 

 so tender that I was unable to extract a fragment 

 more than two or three inches square." ^* Owen, in 

 his memoir on the fossil bones sent home by Darwin, 

 describes and figures two small fragments — "the por- 

 tions of the tesselated bony dermal covering of a 

 Dasypoid quadruped," and these are identified as 

 belonging to the specimen in question by the state- 

 ment that they " were discovered folded round the 

 middle and unguel phalanges," which are also figured 

 on the same plate. ^' 



As evidence of the special interest which Darwin 

 attached to this discovery, it may be mentioned that 

 he at once sent home a fragment of this (or of a 

 similar specimen) to his family, for we find him 

 writing to his sister Catherine, on May 22, 1833 : — 

 " I am quite delighted to find the hide of the Mega- 

 therium " (he uses the term by which such specimens 

 were then generally known) "has given you all some 

 little interest in my employments." ^^ 



Now, in order to appreciate the extraordinary effect 

 of this discovery on young Darwin's mind, we must 

 remember what were the opinions current among 

 geologists when it was made. The views of Cuvier at 

 that date were regarded as not less authoritative in 

 geology than they were in zoology, and in the intro- 

 duction to his magnum opus, the " Ossemens fossiles," 

 the opinions of the great comparative anatomist were 

 pronounced with no uncertain note. He contended 

 that each geological period must have been brought 

 to a close through the sweeping out of existence, by 

 a great cataclysm, of all plant- and animal-life, this 

 being followed by the creation of a perfectly new 

 assemblage of living beings. Cuvier's teaching was 

 made as widely known in this country as it was on 

 the Continent, for Jameson issued a number of editions 

 of a translation of the famous introduction, under the 

 title of " An Essay on the Theory of the Earth " ; and, 

 as von Zittel justly remarks, "Cuvier's catastrophic 

 theory was received with special cordiality in Eng- 



1' " Geological Observations in South America " (1846), p. 84. 



18 //,/rf., p. 86. 



19 ''Zoology of the Beagle," "Fossil Mammalia, ' plate xxxii., and de- 

 scription. 



'■^ " Life and Letters of Charles Darwin," vol. i., p. 245. 



NO. 2192, VOL. 88] 



land." " By none certainly was it adopted more un- 

 reservedly than by Darwm's teachers and friend-. 

 Henslow and Sedgwick. 



Among the books in Darwin's librar)^, now piou- 

 preserved at Cambridge, is a copy of the fifth editi. 

 of the translation of Cuvier's "Essay," bearing i: 

 date of 1827,^^ and 1 think there can be no doubt tL 

 this book was one of those constituting the lif 

 library of reference in the chart-room ol the beai;^ 

 where Darwin worked and slept. Nor can there 

 any hesitation in concluding that with the contei 

 of this book he would be thoroughly familiar. 



This being the case, Darwin found himself con- 

 fronted at Punta Alta with the two startling fa< 

 which he so clearly indicates in his letter to Henslov. 



First, the bones of gigantic and undoubtedly extinct 

 mammals were seen to be associated in the same 

 deposit with shells of living species. He tells Henslow 

 at the time, "They" (the bones) "are mingled with 

 marine shells which appear to me identical with wli • 

 now exist." (He, in fact, collected twenty-five speci 

 all of which D'Orbigny afterwards pronounced to 

 still living.) How, on Cuvier's theory, could such 

 state of things arise? The cataclysm that destroy, n 

 the mammalian must surely have been equally fatal 

 to the mollusca ! 



But the second fact was even more striking and 

 significant. Not only did Darwin obtain the armour 

 of "an enormous armadillo," but among the other 

 remains he identified the jaw of another of th.^ 

 Edentata, and the teeth of rodents similar to thi 

 now living in the district.*' His recent collectic 

 had made him familiar with the peculiar mammal i 

 fauna of South America, and the striking characi' 

 w'hich distinguish it from that of all other portions of 

 the globe, and here, he states, was evidence before 

 his eyes that the mammals of the period immediat- 

 preceding our own, though differing in being m. 

 gigantic, presented a striking family likeness to then.. 

 This was a fact quite inexplicable on the theory o{ 

 wholesale destructions and brand-new creations, but 

 most suggestive, and capable of simple explanation, if 

 the recent forms were descended from the fossil on 

 or both were representative of common ancestors. 



When Charles Darwin arrived home in 1836, a; 1 

 engaged in the preparation of his journal for publica- 

 tion, he found that almost simultaneously with hi> 

 own discovery a similar one had been made with 

 respect to the Australian continent. Clift had identi- 

 fied a number of bones collected in caves in that 

 island as belonging to extinct marsupials, and Janii - 

 son had pointed out the significance of their relati< 

 with the existing fauna.** There can be no doui 

 however, that Darwin was quite unaware of this 

 publication while he was in South America, though 

 he refers to it in writing up his journal. Facts lil-:i 

 these, so familiar to us at the present day, were then 

 quite novel. 



But it is by no means improbable that the mind 

 of the young naturalist was in a specially receptix- 

 condition, when it encountered the shock of thi- 

 important discovery. Darwin has again and again 

 insisted on the revolution produced in his mind on 

 geological questions by the study of the first volume 

 of Lvell's " Principles of Geology," which he took 



-I " History of Geo'ogv and Palscontoloev " (English translation), p. t . 



— "Catalogue of the Library* of Charles Darwin," p. 19. 



^ " More Letters of Charles Darwin," p. 12. 



24 " On the Fossil Bones found in Bone Caves and Bone Breccias in N 

 Holland," Edinh. Ne-w. Phil, foum., vol. x. (1831), pp. 300-7. In 

 paper the list of 'pecies is by Clift, but the remarks are by the e<d' 

 Jameson. The arguments are somewhat weakened by the larger marsupial 

 bones having been mistnken for those of elephant or rhinoceros. It is 

 remarkable that most authors, including Darwin himself, give Clift the 

 credit for the generalis.itions, but this is not borne out by an examination 

 of the paper. 



