Paleozoic

Definition

Of a geologic era within the Phanerozoic eon that comprises the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods from about 542 to 250 million years ago, from the age of trilobites to that of reptiles.

Etymology

From paleo- + -zoic.

Example Sentences

• "‘Itʼs all Paleozoic rock under our feet, this part of the world: to think of it, laid down five hundred million years before, shrugging its shoulders and bringing down the steeples on the churches!’"