Cambrain By kaylaward Oct 1, 1923 Cambrain Earlies dinsouars Oct 1, 1934 Ordovician Oct 1, 1941 Silurian Oct 1, 1950 Devonian Oct 1, 1962 Carboniferous Oct 2, 1974 Tertiary Oct 2, 1986 Jurassic Oct 2, 1998 Cretaceous Oct 2, 2012 Quaternary
