North American Land-Mammal Ages

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