PBDB Interval Range

489.2 - 477.7 Ma

International Chronostratigraphic Timescale			Cambrian of Britain		Ordovician of North America
Ordovician	Late Ordovician	Hirnantian			Cincinnatian	Gamachian				443.8
		Katian				Gamachian				445.2
						Richmondian				446 *
						Maysvillian	Rocklandian †/Shermanian/Ashbyan/Kirkfieldian/Blackriveran/Wildernessian/Trentonian/Franklinian			449.8 *
						Edenian				450.4 *
					Mohawkian	Chatfieldian				451.1 *
		Sandbian				Chatfieldian				453
						Turinian				453.7 *
					Whiterockian		Canadian †	Chazyan †/Marmor		457 *
	Middle Ordovician	Darriwilian								458.4
		Dapingian								467.3
		Dapingian				Rangerian				469.1 *
	Early Ordovician	Floian			Ibexian	Blackhillsian		Jeffersonian †	Cassinian †	470
		Floian				Tulean				473.9 *
		Tremadocian				Tulean				477.7
						Stairsian				480.3 *
						Skullrockian			Demingian †	482 *
Cambrian	Furongian	Stage 10	Merioneth	Dolgellian/Trempealeauan		Skullrockian				485.4
				Dolgellian/Trempealeauan						487.5
				Festiniogian						489.2 *
		Jiangshanian		Festiniogian						489.5
		Jiangshanian		Maentwrogian						493.1 *
		Paibian		Maentwrogian						494
	Miaolingian	Guzhangian	St Davids							497
		Drumian								500.5
		Wuliuan								504.5
	Series 2	Stage 4	Caerfai							509
	Series 2	Stage 3								514
	Terreneuvian	Stage 2								521
	Terreneuvian	Fortunian								529
										538.8