You searched for: “paleozoic
Paleozoic, Palaeozoic (adjective); more Paleozoic, most Paleozoic; more Palaeozoic, most Palaeozoic
Relating to the geologic era extending from the end of the Precambrian to the beginning of the Mesozoic: The Paleozoic period, formally termed "Primary", dates from about 542 to 250 million years ago, from the era of trilobites to those of the reptiles.