TIME UNITS 



^ 



Pleistocene 

 epoch 



Pliocene 

 epoch 



Miocene 

 epoch 



LATE PRE-C. |.§ 

 (PROTEROZOIC) iL 



•V. ft. 



EARtY PRE-C. I IS 



OROGENY 



Cescadian 

 revolution 



Algoman rev. 

 tstfrentian rev. 



DATES 



1,000^00- 





?,000,000,000 

 B.C. 



LIFE RECORD 



C»tnals j Qephants 



Geologic Time Chart. Ascending lines indicate the range In tinne of most 

 of the chief groups of animals and plants. If the line ends in a crossbar, 

 this denotes the time of extinction; if it ends in a dart, the group is still 

 living. 



