A useful mnemonic for remembering the geologic periods of the last half-billion years is: Camels Often Sit Down Carefully, Perhaps Their Joints Creak (Cambrian-Ordovician-Silurian-Devonian-Carboniferous-Permian-Triassic-Jurassic-Cretaceous). The mnemonic unfortunately runs out before the most recent periods: the Paleogene, the Neogene, and the current Quaternary.
