The periods of the geological timescale are:
- Cambrian, Ordovician, Silurian, Devonian, Carboniferous;
- Permian, Triassic, Jurassic, Cretaceous;
- Palaeocene, Eocene, Oligocene, Miocene, Pilocene, Pleistocene, Holocene.
The Mnemonic is
- Camels Often Sit Down Carefully.
- Perhaps Their Joints Creak.
- Probably Early Oiling Might Prevent Premature Harm.