Era
Quaternary
32
Cretaceous
26
Precambrian
11
Paleozoic
10
Pre-Quaternary
9
Tertiary
9
Eocene
8
Holocene
7
Cenozoic
6
Mesozoic
6
Cambrian
5
Ordovician
5
Pennsylvanian
5
Pleistocene
5
Jurassic
4
Silurian
4
Anthropocene
3
Miocene
3
Mississippian
3
Permian
3
Pliocene
3
Paleocene
2
1979
1
Devonian
1
Oligocene
1
Paleogene
1
Proterozoic
1
Triassic
1