古生代

Paleozoic, geological era 545-250m years ago, covering Cambrian 寒武紀|寒武纪, Ordovician 奧陶紀|奥陶纪, Silurian 志留紀|志留纪, Devonian 泥盆紀|泥盆纪, Carboniferous 石炭紀|石炭纪, Permian 二疊紀|二叠纪

to be born / to give birth / life / to grow / raw / uncooked / student

to substitute / to act on behalf of others / to replace / generation / dynasty / age / period / (historical) era / (geological) eon

surname Gu

ancient / old / paleo-