List of Periods
Devonian
Cambrian
Carboniferous
Carboniferous or Devonian
Cretaceous
Devonian
Early Carboniferous
Early Cretaceous
Early Devonian
Early Jurassic
Early Ordovician
Early Tertiary
Jurassic
Late Cambrian
Late Cretaceous
Late Devonian
Late Ordovician
Late Tertiary
Lower Cambrian
Lower Cretaceous
Lower Devonian
Lower Silurian
Middle Cretaceous
Middle Devonian
Middle Ordovician
Middle Silurian
Ordovician
Permo-Carboniferous
Quaternary
Recent
Silurian
Tertiary
Upper Cretaceous
Upper Devonian
Upper Eocene
Upper Ordovician
Upper Silurian