218 AyXALS yEW YOBK ACADEMY OE SCIEyCES 



C-ETNTOZOIC . 



Quaternary Age of Man 



Tertiary Age of Mammals 



We thus enter a new Ceenozoie faunal phase, the Seventh. TThen its 

 transitions are complete the world wears an entirely new and somewhat 

 impoverished aspect : the Xorth has banished all the chief sontherly 

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

 Xew Worlds, namely : Pala?arctic. Xearetic. Oriental, Ethiopian. Xeo- 

 tropical. 



Sevexth Fauxal Phase — Quaterxaey 



ix the xoetheex he^^iisphere the glaciae epoch. very gradual 

 extixctiox or expulsiox oe southeex types of african-, south 

 asiatic axd south aimericax origix from the xortherx. or 



HOLAECTIC PlEAL:M. FIRST APPEAEAXCE IX CEXTRAL EUROPE .-^'D 

 X^OETH AINIERICA OF THE CIRCUMPOLAR TUXDRA FAUXA. IX EUROPE 

 OF THE STEPPE FAUXA. IX XORTH A2*IEEICA EXTIXCTIOX OF THE 

 PtEMATXIXG LAEGE EXDEltlC QUADEUPEDS. THIRD AXD FIXAL MOD- 

 EEXIZATIOX OF EUEOPE AXD XOETH AINIEEICA BY THE HARDY FOEEST,. 

 AIEADOW AXD INIOUXTAIX EUIMIXAXTS AXD THE CAEXIVOEES. 



The grand geologic divisions of the Quaternary in the Xew and Old 

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

 with the Holocene. 



II. HoLocEXE. or Recext Epoch. Mammals of prehistoric and recent 

 times. Domestication. 

 I. Pleistocexe. or Glacial Epoch. 



3. PosTGLACLij:. Mammals of tundra and steppe type gradually 

 disappearing or retreating. Mammals of existing north tem- 

 g i 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. 



MEAXS OF ESTABLISHIXG THE TIIME DIVISIOXS OF THE QUATEEXARY 



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 bv a review of the ereat time divisions 



U 



