164 GEOLOGY OF PATAGONIA. [CHAP. vm. 



At Port St. Julian,* in some red mud capping the gravel on the 

 90-feet plain, I found half the skeleton of the Macraucheuia Pata- 

 ehonica, a remarkable quadruped, full as large as a camel. It 

 belongs to the same division of the Pachydermata with the rhino- 

 cerous, tapir, and palseotherium ; 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 llama. 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 

 Macrauchenia was intombed, it is certain that this curious quad- 

 ruped 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, 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 living species of Ctenomys and Hydrochserus, 

 are most interesting 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 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. 



* I have lately heard that Capt. Sulivan, R.N., lias found numerous 

 fossil bones, embedded in regular strata, on the banks of the R. Gallegos, 

 in lat. 51 4'. Some of the bones are large ; others are small, and appear 

 to have belonged to an armadillo. This is a most interesting and 

 important discovery. 



