.Tanuaey 1, 1894.] 



KNOWLEDGE 



ably an inhabitant of swamps and marshes ; while the 

 still more extraordinary Macrauclienia, with its slender, 

 camel-like neck, and long three-toed limbs, probably 

 stalked over the plains, cropping here and there the foliage 

 from some tree or copse. Rodents, nearly related to 

 existing South American types, were likewise common ; 

 and there were also certain large carnivores, such as a 

 species of sabre-toothed tiger, and a huge bear-like creature. 

 With the exception of these carnivores, together with the 

 guanacos, horses, deer, and elephants which are unknown 

 in the older formations, and are therefore probably late 

 immigrants from the north, all the auimalsof the Pampean 

 formation are peculiar to South America. A further 

 distinctive feature of this fauna is the large bodily size 

 attained by so many of its representatives, this being 

 especially the case with the glyptodons, mylodons, 

 megatheres, guanacos, mastodons, macrauchenia, and 

 toxodon, all of which would co)ne under the designation of 

 giant animals. In this respect the Pampean fauna cor- 

 responds with that of the Pleistocene period of Europe, 

 with which it also agrees approximately in age, seeing 

 that there is evidence of the contemporaneous existence of 

 man with several of the extinct mammals. 



In certain parts of the Pampean formation the remains 

 of these animals occur in extraordinary profusion, and 

 generally in a most perfect state of preservation. At times 

 they are foimd sticking out from the perpendicular cHffs 

 or tinmncas bordering the river-valleys, while many are 

 met with in sinking wells or making other excavations. 

 In well-digging, of course, only a portion of a skeleton is 

 obtained in the case of a large animal, which is the cause 

 of the imperfect condition of the majority of specimens in 

 European museums, and it is only when excavations, like 

 those during the construction of the docks at La Plata or 

 Buenos Ayres, are made that entire skeletons are obtained, 

 unless, indeed, special works are undertaken for the 

 purpose of obtaining fossils. It does not, however, appear 

 that the remains are at all evenly distributed through the 

 Pampean, some localities being much richer than others, 

 and among these Lujan (pronounced Luhivn), near Buenos 

 Ayres, being especially notable. Although the museum 

 of th6 Eoyal College of Surgeons contains an entire 

 skeleton of a megathere, together with the shell of a 

 glyptodon, while the British Museum is the fortunate 

 possessor ot a complete specimen of a mylodon, the 

 museums of Europe give us but a very poor idea of the 

 number and beautiful preservation of these marvellous 

 fossils. To gain any idea of the true state of the case it is 

 necessary to visit (as I have recently had the opportunity 

 of doing) the museums of Buenos Ayres and La Plata, 

 and more especially the latter. There the visitor will be 

 absolutely lost in astonishment at the long array of 

 perfectly mounted skeletons of numbers of these creatures, 

 while the unmounted skeletons and isolated bones dis- 

 played in the wall-cases will convince him that I am 

 not exaggerating when I speak of Argentina as a land 

 of skeletons. 



That the animals I have spoken of shoitld have died off 

 one after another through the long ages during which the 

 Pampean mud was accumulating is in accordance with 

 what we should expect to occur, while the perfection of 

 their preservation is sufficiently accounted for by the 

 nature of the deposit itself. The marvel, however, is in 

 regard to the total disappearance of the whole of the 

 larger forms and the reduction of the fauna of the pampas 

 to its present condition, together with the concomitant 

 loss of the forests. It is not that the country is uusuited 

 at the present day to the existence of the larger types of 

 animal life, as witness the countless herds of horses and 



cattle with which its plains are now covered, together with 

 the luxuriance and rapidity with which many kinds of 

 trees flourish when introduced. Neither, I think, can it 

 be due to a glacial period (although there appears to be 

 evidence of the prevalence of a cold period in Patagonia), 

 since any glaciation of the pampas would have assuredly 

 removed the greater part of the alluvial formation, besides 

 having left indisputable evidence of its presence. Man, 

 too, cannot be credited with tbe extinction of either the 

 fauna or the flora. It has been suggested that the number 

 of guanaco with which the country was overrun previous 

 to European settlement may have caused the destruction 

 of the forests ; but we must remember that similar animals 

 existed in greater variety during the Pampean period, 

 while even if the disappearance of trees were due to their 

 agency, this would have had no effect on plain-loving 

 forms like horses. That the disappearance of the latter 

 animals may have been due to the number of pumas is 

 another suggestion ; but it will be obvious that this could 

 have had nothing to do with the destruction of gigantic 

 creatures like the glyptodons and the megatheres. The 

 problem is further complicated by the circumstance that 

 the remains of many of these creatures occur in caverns 

 in the interior of Brazil, where the climate is stUl, and 

 probably always has been, tropical. It would seem, there- 

 fore, that we must be content to regard the depletion of 

 the fauna and flora of Argentina as one of the luisolved 

 problems of science. 



So much space has been occupied by the foregoing 

 survey of the Pampean fauna and the preliminary obser- 

 vations on the present condition of the country, that but 

 little remains to devote to the older formations. At 

 Parana, and also on the coast at Monte Hermosa, near 

 Bahia Blanca, there occur, however, certain Tertiary 

 deposits which are evidently somewhat older than the 

 Pampean beds, although contaiuing a clos ly 'llitd fauna. 

 The most interesting feature connected with «'|j, formation 

 (which may probably be correlated with the upper Pliocene 

 of Europe) is that the mammals are for the most part of 

 smaller size than their relatives of the Pampean ; this 

 being especially shown by the glyptodons, and by those 

 ground sloths known as scelidotheres, which are near 

 allies of the mylodons. When we reach the still older 

 beds of Santa Cruz, in Patagonia, which are probably of 

 Miocene age (although they have been correlated with the 

 lower Eocene, we find not only this diminution in the size 

 of the mammals still more marked, but we likewise notice 

 the disappearance of all the northern forms, such as deer, 

 horses, guanaco, and elephants, thus showing that we have 

 reached the period when South America was disconnected 

 from the northern half of the continent, and possessed an 

 absolutely peculiar fauna. Instead of glyptodons with a 

 shell of eight or ten feet in length, we meet with species 

 in which the carapace did not measure more than a yard ; 

 while in place of mylodons bigger than a rhinoceros, we 

 are confronted with a species not so large as a Highland 

 sheep. The camel-like Moci-auclwnia was likewise repre- 

 sented by several much smaller allies, while the various 

 species of Xesodon, which represented the gigantic Toxodon 

 of the Pampean, were either small or moderate-sized 

 animals. Somewhat curiously, there were, however, 

 several kinds of gigantic flightless birds which are quite 

 unknown in the higher beds, and appear to have been 

 allied to the flying birds of the present day, instead of, as 

 might have been expected, to the ostriches and rheas. 



In subsequent articles we propose to enter into the 

 consideration of the leading structural peculiarities of some 

 of the most remarkable of the extinct mammals from the 

 " Land of Skeletons." 



