The standard NALMAS used in the arrangement of the UCMP collection are listed below with reference to their appropriate epoch for general reference.
 

Pleistocene     Rancholabrean     Irvingtonian Pliocene     Blancan Miocene     Hemphillian (extends into Pliocene)     Clarendonian     Barstovian     Hemingfordian  Oligocene     Arikareean (extends into Miocene)     Whitneyan     Orellan Eocene     Chadronian     Duchesnean     Uintan     Bridgerian     Wasatchian (may extend into Paleocene) Paleocene     Clarkforkian     Tiffanian     Puercan

For a detailed current discussion of the Land Mammal Age boundaries, read

Woodburne, M.O. and C.C. Swisher III.  1995. Land mammal high-resolution geochronology, intercontinental overland dispersals, sea level, climate, and vicariance, pp. 337-364 in W.A. Berggren, D.V. Kent, M-P. Aubry and J. Hardenbol (eds.) Geochronology, Time Scales, and Global Stratigraphic Correlations: Unified Temporal Framework for an Historical Geology, SEPM Spec. Pub. no. 54