THE VOYAGE OF THE BEAGLE 187 



step-formed plains, which must have been modelled and 

 upraised before the mud was deposited in which the Macrau- 

 chenia was entombed, it is certain that this curious quadru- 

 ped lived long after the sea was inhabited by its present 

 shells. I was at first much surprised how a large quadruped 

 could so lately have subsisted, in lat. 49 15', on these 

 wretched gravel plains, with their stunted vegetation ; but 

 the relationship of the Macrauchenia to the Guanaco, now 

 an inhabitant of the most sterile parts, partly explains this 

 difficulty. 



The relationship, though distant, between the Macrau- 

 chenia and the Guanaco, between the Toxodon and the 

 Capybara, the closer relationship between the many extinct 

 Edentata and the living sloths, ant-eaters, and armadillos, 

 now so eminently characteristic of South American zoology, 

 and the still closer relationship between the fossil and liv- 

 ing species of Ctenomys and Hydrochaerus, are most inter- 

 esting facts. This relationship is shown wonderfully as 

 wonderfully as between the fossil and extinct Marsupial 

 animals of Australia by the great collection lately brought 

 to Europe from the caves of Brazil by MM. Lund and Clau- 

 sen. In this collection there are extinct species of all the 

 thirty-two genera, excepting four, of the terrestrial quadru- 

 peds now inhabiting the provinces in which the caves occur ; 

 and the extinct species are much more numerous than those 

 now living: there are fossil ant-eaters, armadillos, tapirs, 

 peccaries, guanacos, opossums, and numerous South Ameri- 

 can gnawers and monkeys, and other animals. This wonder- 

 ful relationship in the same continent between the dead and 

 the living, will, I do not doubt, hereafter throw more light 

 on the appearance of organic beings on our earth, and their 

 disappearance from it, than any other class of facts. 



It is impossible to reflect on the changed state of the 

 American continent without the deepest astonishment. For- 

 merly it must have swarmed with great monsters: now we 

 find mere pigmies, compared with the antecedent, allied 

 races. If Buffon had known of the gigantic sloth and arma- 

 dillo-like animals, and of the lost Pachydermata, he might 

 have said with a greater semblance of truth that the creative 

 force in America had lost its power, rather than that it had 



