Geologic Time Scale

 

ERA PERIODS AND SYSTEMS EPOCHS AND SERIES MILLIONS OF YEARS AGO BIOLOGICAL EVENTS
C Quaternary Holocene 0.01  
E   Pleistocene 1.0 Earliest Humans
N Tertiary Pliocene 5 Earliest Hominids
O   Miocene 24 Earliest Primates
Z   Oligocene 37  
O   Eocene 58 Earliest grasses, division of mammals
I   Paleocene 65 Earliest large mammals
C        
EXTINCTION OF DINOSAURS AT THE CRETACEOUS-TERTIARY BOUNDARY 65 MILLION YEARS AGO
 
M Cretaceous Upper 98  
E   Lower 144 Earliest flowering plants, dinosaurs in ascendance
S Jurassic   208 Earliest birds and mammals
O Triassic   245 Age of dinosaurs begins
Z        
O        
I        
C        
 
P Permian   286 Age of the amphibians
A Carboniferous     Widespread coal swamps
L Pennsylvanian   320 Earliest reptiles
E Mississippian   360 Earliest winged insects
O Devonian   408 Earliest vascular plants (ferns and mosses) and amphibians
Z Silurian   438 Earliest land plants and insects
O Ordovician   505 Earliest corals
I Cambrian   570 Earliest fish, Age of Trilobites
C        
 
P        
R        
E        
C Proterozoic Eon   2500 Earliest colonial algae and soft-bodied invertebrates
A        
M        
B        
R Archean Eon   4000 Life appears: earliest algae and primitive bacteria
I        
A        
N