IODP SEDIS - Thesaurus -

Trentonian
BT	Chronostratigraphic Units
	.Phanerozoic
	..Paleozoic
	...Ordovician
	....Middle Ordovician
	.....Trentonian
NT	Trenton Group
RT	Champlainian
SN	North America. Upper Mohawkian, above Blackriverian.