1834.] TYPES OF ORGANIZATION CONSTANT. 125 



palaeotherium ; but in the structure of the bones of its long neck it 

 shows a clear relation to the camel, or rather to the guanaco and llam^ 

 From recent sea-shells being found on two of the higher step-formed 

 plains, which must have been modelled and upraised before the mud 

 was deposited in which the Macrauchema was intombed, it is certain 

 that this curious quadruped 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 Macrauchenia and the 

 Guanaco, betxveen the Toxodon and the Capybara, the closer relation- 

 ship 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 

 living species of Ctenomys and Hydrochaerus, are most interesting 

 facts. This relationship is shown wonderfully as wonderfully as 

 between the fossil and extinct Marsupial animals of Australiaby the 

 great collection lately brought to Europe from the caves of Brazil by 

 MM. Lund and Clausen. In this collection there are extinct species of 

 all the thirty-two genera, excepting four, of the terrestrial quadrupeds 

 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 American gnawers and monkeys, and other animals. 

 This wonderful 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. Formerly 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 armadillo-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 never 

 possessed great vigour. The greater number, if not all, of these 

 extinct quadrupeds lived at a late period, and were the contemporaries 

 of most of the existing sea-shells. Since they lived, no very great 

 change in the form of the land can have taken place. What, then, has 

 exterminated so many species and whole genera ? The mind at first is 

 irresistibly hurried into the belief of some great catastrophe ; but thus 

 to destroy animals, both large and small, in Southern Patagonia, in 

 Brazil, on the Cordillera of Peru, in North America up to Behring's 

 Straits, we must shake the entire framework of the globe. An exami- 

 nation, moreover, of the geology of La Plata and Patagonia, leads to 

 the beli?f that all the features of the land result from slow and gradua* 

 changes. It appears from the character of the fossils in Europe, Asia, 



