A Guide to the Dinosaurs of Colorado

The Age of Dinosaurs

Era	Period	Epoch	Age	Duration	Ma*
CENOZOIC	Tertiary	Paleocene	Danian	4.8	65
M E S O Z O I C	Cretaceous	Late	Maastrichtian	8	73
			Campanian	10	83
			Santonian	4.5	87.5
			Coniacian	1	88.5
			Turonian	2.5	91
			Cenomanian	6.5	97.5
		Early	Albian	15.5	113
			Aptian	6	119
			Barremian	6	125
			Hauterivian	6	131
			Valanginian	7	138
			Berriasian	6	144
	Jurassic	Late	Tithonian	6	150
			Kimmeridgian	6	156
			Oxfordian	7	163
		Middle	Callovian	6	169
			Bathonian	6	175
			Bajocian	6	181
			Aalenian	7	188
		Early	Toarcian	6	194
			Pliensbachian	6	200
			Sinemurian	6	206
			Hettangian	7	213
	Triassic	Late	Rhaetian	6	219
			Norian	6	225
			Carnian	6	231
		Middle	Ladinian	7	238
			Anisian	5	243
		Early	Spathian	1.25	244.25
			Smithian	1.25	245.5
			Dienerian	1.25	246.75
			Griesbachian	1.25	248
Dates are from Harland, et.al. (1982) * Millions of Years Ago.