Mnemonic Device: Cows Often Sit Down Carefully. Perhaps, Their Joints Creak? Persistent, Early Oiling Might Prevent Painful Rheumatism. Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleocene, Eocene,

Mnemonic Device: Cows Often Sit Down Carefully. Perhaps, Their Joints Creak? Persistent, Early Oiling Might Prevent Painful Rheumatism. Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian, Triassic, Jurassic, Cretaceous, Paleocene, Eocene,