Era
20th century
12
19th century
8
Devonian
6
21st century
5
Pennsylvanian
5
1865-1950
4
1867-1912
4
1871-1948
4
1876-1941
4
Civil War, 1861-1865
4
Mississippian
4
1827-1900
3
1864-1922
3
Ordovician
3
Quaternary
3
Silurian
3
To 1795
3
To 1803
3
1787-1865
2
1831-1881
2
1857-1930
2
1945-
2
1951-
2
Colonial period, ca. 1600-1775
2
-1913
1
1720?-1782
1
1721-1808
1
1734-1818
1
1738-1824
1
1742-1823
1
1743-1798
1
1750-1815
1
1765-1815
1
1765-1843
1
1767-1853
1
1771-1839
1
1771-1870
1
1783-1815
1
1783-1863
1
1786-1859
1
1787-1805
1
1787-1834
1
1790-1794
1
1790-1834
1
1793-1886
1
1796-1890
1
1805-1866
1
1808-1873
1
1825-1864
1
1836-1908
1
more ...