500 GEOLOGY. 



cial epoch came on, the northern types were pressed well to the south 

 but not to the extreme extent of the preceding epoch. 



The deposits of the third interglacial epoch embrace, in some places, 

 temperate marine faunas, and in others arctic forms. The mam- 

 malian fauna embraced the Irish deer, the horse, the mammoth, and 

 the woolly rhinoceros. The evidence favors the belief that the climate 

 became ameliorated to a degree congenial to a cool-temperate fauna, 

 but not to a warm-temperate or subtropical fauna. 



During the remaining epochs, the oscillations were apparently 

 much less wide, ranging between cold-temperate and sub-arctic in 

 northern and middle Europe; in short, the to-and-fro migrations of 

 the life appear to have died away in oscillations of decreasing ampli- 

 tude, corresponding to the subsiding oscillations of the glacial stages. 



The Pleistocene Life of the Southern Hemisphere. 



Life in South America. — While the Pleistocene life of North America 

 and Europe bore a close similarity to one another, that of South America 

 had a character quite its own. The major fauna was composed of 

 two great elements, (1) the gigantic sloths and armadillos, which were 

 indigenous to that country, and (2) the descendants of the Pliocene 

 mammals which had migrated from North America. It is possible, 

 on the other hand, that a portion of the extinct South American fauna, 

 referred to the Pleistocene, really belonged to the late Pliocene. The 

 indigenous element of the fauna was rendered remarkable by the abun- 

 dance and extraordinary dimensions of the great extinct sloths and 

 armadillos. Among the northern immigrants were horses, masto- 

 dons, llamas, tapirs, wolves, and a large variety of rodents. The 

 gigantic character and seeming great abundance of the fauna, taken 

 as a whole, and especially that of the edentates, seems out of har- 

 mony with the repressive conditions w r hich might reasonably be inferred 

 from the crowding of the faunas toward the tropics by the advance 

 of the glacial climates from the higher latitudes, and by its develop- 

 ment on the mountains and plateaus. It might naturally be antici- 

 pated that there would result a sharp struggle for existence, attended 

 by the destruction of the least adapted forms and the numerical reduc- 

 tion of the whole. Just such a reduction has taken place since, if not 

 then, and this seems to give some force to the suggestion that the 



