Era
20th century
18
18th century
5
19th century
3
1743-1794
2
17th century
2
1834-1907
2
1918-1998
2
1932-
2
21st century
2
Cretaceous
2
Paleozoic
2
Quaternary
2
1627-1691
1
1718-1784
1
1731-1810
1
1733-1804
1
1742-1786
1
1766-1844
1
1776-1856
1
1778-1829
1
1791-1867
1
1809-1882
1
1844-1930
1
1850-1936
1
1861-1912
1
1867-1934
1
1875-1946
1
1881-1957
1
1883-1971
1
1896-1980
1
1903-1972
1
1912-2008
1
1916-2000
1
1917-1979
1
1925-
1
1933-2021
1
1937-
1
1944-
1
Cambrian
1
Holocene
1
Jurassic
1
Mesozoic
1
Miocene
1
Republic, 1912-1949
1
Tertiary
1