Cretaceous 114
Quaternary 92
Paleozoic 33
Precambrian 33
Cenozoic 26
Tertiary 23
Jurassic 20
Mesozoic 18
Civil War, 1861-1865 17
Pre-Quaternary 15
Eocene 14
Permian 13
Pennsylvanian 12
20th century 10
Cambrian 8
19th century 7
Paleocene 7
Ordovician 6
Pleistocene 6
Proterozoic 6
Partition, 1995 5
Revolution, 1775-1783 4
Devonian 3
Holocene 3
Miocene 3
Mississippian 3
Neogene 3
Paleogene 3
Triassic 3
1831-1897 2
1866-1895 2
1945- 2
1979 2
1979- 2
21st century 2
Oligocene 2
To 146 B.C. 2
1200-1259 1
1254-1323? 1
1470-1519 1
1485-1547 1
1596-1673 1
1728-1801 1
1729-1824 1
1735-1809 1
1770-1838 1
1774-1809 1
1781-1870 1
17th century 1
1810-1873 1
1815-1871 1
1862-1865 1
1862-1877 1
1871-1918 1
1902-1996 1
1913 1
1918-1945 1
1930-2006 1
1933-1945 1
1935- 1
1944- 1
1945-1989 1
1945-1992 1
1946- 1
1947- 1
1949-1976 1
1960-1988 1
1961- 1
1962- 1
1963 1
1964 1
1965-1980 1
1970 1
1970-1973 1
1971 1
1972- 1
1973-1988 1
1980-2020 1
1981-2001 1
1990 1
1991- 1
2000- 1
2002- 1
2012 1
2017 1
2023 1
476-1492 1
800-1444 1
Anglo-Saxon period, 449-1066 1
Conquest, 1519-1540 1
Middle Ages, 600-1500 1
Pliocene 1
Pre-Cenozoic 1
Silurian 1
To 1500 1
To 70 A.D. 1
War of 1812 1