Triassic
Cretaceous
Devonian
Calymmian
Ordovician
Cambrian
Orosirian
Ectasian
Siderian
Stenian
Mesozoic
Jurassic
Cryogenian
Statherian
Stennian
Miocene
Paleozoic
Rhyacian
Aptian
Neozoic
Silurian
Neogene
Paleogene
Quaternary
Precambrian
Tonian
Carboniferous period
Triassic-Jurassic extinction event
Cenomanian
Coniacian
Carboniferous
Triassic period
Cycadales
order Cycadales
Eocene
Ediacaran
Permian period
Permian
tertiary
Laramide
finicretaceous
Santonian
Maastrichtian
Acadian
dinosaur
Hettangian
-cene
-zoic
Mesolithic
Nectarian
Ordovician period
K-T boundary
lower boundary
mesocenozoic
Guadalupian
Jurassic period
Eratosthenian
Middle Stone Age
Oligocene
coal gap
Preclassic
Callovian
Missippian period
Lower Carboniferous period
Kimmeridgian
Bathonian
Sinemurian
Pliensbachian
Embrian
Mississippian
pre-Jurassic
Toarcian
Lower Carboniferous
Bajocian
euxinia
Pennsylvanian period
recent
Upper Carboniferous period
allochronic
Archaeozoic
Cenozoic
eustreptospondylus
pre-Nectarian
Pennsylvanian
Paleolithic
Tethys
Upper Carboniferous
C17
neolithic