Ordovician Period Mittleres Ordovizium オルドビス紀中期 Early Ordovician Epoch Darriwilian Age a1.1.3.5.2 középső-ordovícium Kesk-Ordoviitsium older bound -470.0 +|-1.4 Ma mellersta ordovicium 中期オルドビス紀 Vidurinis Ordovikas Keski-Ordoviikki Ordovícico Médio Midtre ordovicium Middle Ordovician Paleozoic Era Floian Age Midden Ordovicium younger bound -458.4 +|-0.9 Ma Geologic Time Scale (2018) 中奥陶统 Střední ordovik Middle Ordovician Epoch Late Ordovician Epoch Ordovicien moyen Base of Late Ordovician Dapingian Age Sandbian Age Phanerozoic Eon 中奥陶世 Ordovícico Medio Środkowy Ordowik Среден Ордовик ordoviciano medio Mellem Ordovicium Base of Middle Ordovician srednji ordovicij stredný ordovik