24 



Schuchert and Barrell — Revised Geologic 



GEOLOGIC CHRONOLOGY FOR NORTH AMERICA. 



(i) Classification based on Superposition of Strata, and Erosion Intervals. 

 Correlation by Means of Fossils. 



Eras 



Major 

 Divisions 



Periods 



Epochs 



Advances in Life 



Dominant 

 Life 



PSY- 

 CHO- 

 ZOIC 







Eecent 



(Alluvial 



or 



Post-Glacial) 



'0 



> 

 <D 



M 

 a 



^3 



03 

 

 m 

 03 

 O 



Eise of world civili- 

 zation 

 The era of mental life 



AGE OF 



MAN 





QUATER- 

 NARY 



Glacial 



Pleistocene 



Periodic glaciation 

 Extinction of great 

 mammals 





U 'h 



J 



Tertiary 



Late Tertiary 

 (Neogene) 



Pliocene 



Transformation of 

 man-ape into man 



AGE OF 



MAMMALS 



Miocene 



Culmination of 

 mammals 



AND 





Early Tertiary 

 (Paleogene) 



Oligocene 



Rise of higher 

 mammals 



MODERN 

 FLORAS 





Eocene 



Vanishing of archaic 

 mammals 







Late 

 Mesozoic 



Epi-Mesozoic Interval 



| 



'o 



> 

 « 



a 



03 

 f- 

 e3 

 ►J 



Rise of archaic 

 mammals 





^ 



Cretaceous 



Lance 



Extinction of great 

 reptiles 





^3 



Montanian 

 Coloradian 



Extreme specializa- 

 tion of reptiles 



AGE OF 

 REPTILES 



MESO 



(Mediev 



Comanchian 





Rise of flowering 

 plants 



Early 



Jurassic 





Rise of birds and 

 flying reptiles 







Mesozoic 



Triassic 





Rise of dinosaurs 





[Continued on the next page.] 



