Era
Cretaceous
235
Tertiary
147
Eocene
88
Paleozoic
86
Precambrian
86
Miocene
83
Quaternary
80
Cenozoic
79
Ordovician
77
Jurassic
71
Mississippian
65
Pennsylvanian
64
Devonian
59
Permian
56
Pleistocene
52
Triassic
50
Cambrian
45
Mesozoic
44
Silurian
42
Oligocene
39
Pliocene
32
Carboniferous
31
Proterozoic
28
Holocene
21
Paleocene
21
Archaean
7
Neogene
5
1834-1902
4
1913-1972
2
20th century
2
Paleogene
2
1818-1891
1
19th century
1