Era
Cretaceous
16
Revolution, 1775-1783
10
20th century
7
Tertiary
6
Colonial period, ca. 1600-1775
4
Proterozoic
4
Triassic
4
1951-
3
Miocene
3
Ordovician
3
Paleozoic
3
Precambrian
3
1847-1931
2
19th century
2
Cenozoic
2
Devonian
2
Eocene
2
Mesozoic
2
Paleocene
2
Pleistocene
2
Silurian
2
To 1775
2
1691-1756
1
1712-1779
1
1744-1809
1
1793-
1
1816-1902
1
1856-1924
1
1858-1942
1
1894-1975
1
1895-1983
1
1901-1909
1
1909-1913
1
1910
1
1912
1
1934-2017
1
1937-
1
1960-
1
1971-
1
1981-1989
1
1984-
1
Archaean
1
Dovanian
1
Jurassic
1
To 1791
1