218 ANNALS NEW YORK ACADEMY OF SCIENCES 



G-^NOZGIC 



Quaternary Age of Man 



Tertiary Age of Mammals 



We thus enter a new Csenozoic faunal phase, the Seventh. When its 

 transitions are complete the world wears an entirety new and somewhat 

 impoverished aspect: the North has banished all the chief southerly 

 forms and established the five modern zoological regions of the Old and 

 Xew Worlds, namely: Palaearctic, Nearctic, Oriental, Ethiopian, Neo- 

 tropical. 



Seventh Faunal Phase — Quaternary 



in the northern hemisphere the glacial epoch. very gradual 

 extinction or expulsion of southern types of african, south 

 asiatic and south american origin from the northern, or 

 holarctic realm. first appearance in central europe and 

 north america of the circumpolar tundra fauna, in europe 

 of the steppe fauna. in north america extinction of the 

 remaining large endemic quadrupeds. third and final mod- 

 ernization of europe and north america by the hardy forest, 

 meadow and mountain ruminants and the carnivores. 



The grand geologic divisions of the Quaternar}*' in the New and Old 

 Worlds are the same, namery, beginning with the Pleistocene and closing 

 with the Holocene. 



II. Holocene. or Recent Epoch. Mammals of prehistoric and recent 

 times. Domestication. 

 I. Pleistocene, or Glacial Epoch. 



3. Postglacial. Mammals of tundra and steppe type gradually 

 disappearing or retreating. Mammals of existing north tem- 

 perate type multiplying. 

 2. Glacial. Period of successive glacial advances and interglacial 

 retreats. Mammals of extinct and existing species com- 

 mingled. 

 1. Peeglacial. Period of the lowering of temperature in the 

 northern hemisphere and modification of plant and animal 

 life. 



MEANS OF ESTABLISHING THE TIME DIVISIONS OF THE QUATERNARY 



The fluctuations of climate and of the plant and animal life of the 

 Pleistocene are so numerous, so widespread, and so profound that it 

 seems best to introduce the subject by a review of the great time divisions 



y- 



