奥陶纪 Ordoviitsium オルドビス紀 Floian Age younger bound -443.8 +|-1.5 Ma Ordovik a1.1.3.5 Silurian Period Late Ordovician Epoch Ordovikas Cambrian Period Paleozoic Era Dapingian Age Darriwilian Age Geologic Time Scale (2019) Hirnantian Age ordovik Cambrian Stage 10 Age ordovícium Ordoviikki Ordovician Period Llandovery Epoch Ordovician Base of Ordovician Ordowik ordovicij Katian Age Ordovizium Base of Silurian ordoviciano Ordovicium Ordovicium Ordovicium older bound -485.4 +|-1.9 Ma Ордовик Middle Ordovician Epoch Furongian Epoch Phanerozoic Eon Early Ordovician Epoch Ordovícico Ordovícico Sandbian Age Tremadocian Age Ordovicien ordovicium Rhuddanian Age