19th century 15
Civil War, 1861-1865 15
Cretaceous 13
20th century 12
1775-1865 8
1924- 8
Eocene 6
1865-1950 4
Colonial period, ca. 1600-1775 4
Paleozoic 4
18th century 3
1929-1968 3
1951- 3
1962-2007 3
Tertiary 3
1977-1981 2
Devonian 2
Pleistocene 2
Quaternary 2
Revolution, 1775-1783 2
Silurian 2
-1913 1
1696-1785 1
1703-1791 1
1780-1856 1
1803-1879 1
1804-1863 1
1808-1844 1
1809-1893 1
1810-1885 1
1812-1883 1
1812-1891 1
1823-1862 1
1828-1864 1
1834-1907 1
1835-1930 1
1837-1910 1
1845-1922 1
1847-1865 1
1847?-1913 1
1861-1865 1
1875-1899 1
1884-1915 1
1900-1949 1
1918-1932 1
1919-1933 1
1926-1990 1
1931-1990 1
1933-1945 1
1937- 1
1942-2021 1
1945- 1
1946- 1
1965- 1
1974-1977 1
2001-2009 1
2005 1
2017-2021 1
2020 1
Holocene 1
Neogene 1
Ordovician 1
To 1775 1
To 1791 1