164 EXTINCT FOSSIL MAMMALIA. [Ch. XIIL 



South America ; but these few exceptions can by no means invalidate 

 the rule which has been thus expressed by Professor Owen, " that in the 

 highest organized class of animals the same forms were restricted to the 

 same great provinces at the Pliocene periods as they are at the pres- 

 ent day." 



However modern, in a geological point of view, we may consider the 

 Pleistocene epoch, it is evident that causes more general and powerful 

 than the intervention of man have occasioned the disappearance of the 

 ancient fauna from so many extensive regions. Not a few of the species 

 had a wide range ; the same Megatherium, for instance, extended from 

 Patagonia and the river Plata in South America, between latitudes 31° 

 and 39° south, to corresponding latitudes in North America, the same 

 animal being also an inhabitant of the intermediate country of Brazil, 

 where its fossil remains have been met with in caves. The extinct ele- 

 phant, likewise, of Georgia {ElepTias primigenius) has been traced in a 

 fossil state northward from the river Alatamaha, in lat. 33° 50' N. to the 

 polar regions, and then again in the eastern hemisphere from Siberia to 

 the south of Europe. If it be objected that, notwithstanding the adapta- 

 tion of such quadrupeds to a variety of climates and geographical con- 

 ditions, their great size exposed them to extermination by the first hunter 

 tribes, we may observe that the investigations of Lund and Clausen in 

 the ossiferous limestone caves of Brazil have demonstrated that these 

 large mammalia were associated with a great many smaller quadrupeds, 

 some of them as diminutive as field mice, which have all died out together, 

 while the land shells formerly their contemporaries still continue to exist 

 in the same countries. As we may feel assured that these minute quad- 

 rupeds could never have been extirpated by man, especially in a country 

 so thinly peopled as Brazil, so we may conclude that all the species, small 

 and great, have been annihilated one after the other, in the course of in- 

 definite ages, by those changes of circumstances in the organic and inor- 

 ganic world which are always in progress, and are capable in the course 

 of time of greatly modifying the physical geography, climate, and all 

 other conditions on which the continuance upon the earth of any living 

 being must depend.* 



The law of geographical relationship above alluded to, between the 

 living vertebrata of every great zoological province and the fossils of the 

 period immediately antecedent, even where the fossil species are extinct, 

 is by no means confined to the mammalia. New Zealand, when first 

 examined by Europeans, was found to contain no indigenous land quad- 

 rupeds, no kangaroos, or opossums, like Australia ; but a wingless bird 

 abounded there, the smallest living representative of the ostrich family, 

 called Kivi, by the natives (Apteryx). In the fossils of the Post-Pliocene 

 and Pleistocene period in this same island, there is the like absence of 

 kangaroos, opossums, wombats, and the rest ; but in their place a pro- 

 digious number of well-preserved specimens of gigantic birds of the stru- 

 thious order, called by Owen Dinornis and Palapteryx, which are en- 

 * See Principles of Geology, chaps, xli. to xliv. 



