Secondary subdivision is by Storage Age arranged by their order in geologic time. For Africa and Asia the Storage Ages are the epochs and their standard subdivisions (early/late or early/middle/late). For Australia/New Zealand it is by now-outmoded faunal ages that broadly correspond to local faunas. For the Americas, the appropriate Land Mammal Ages (NALMAs and SALMAs) are used.
Tertiary subdivision is alphabetically by Country, except for North America where it is alphabetically by state. Mexico is treated as a single "state" in this scheme, but Canadian provinces appear individually.
Below that, subdivision is alphabetically by Formation and Locality Prefix+Locality Number, numerically arranged within a given prefix. Please note that localities starting with prefixes other than a 'V' precede the more common V-localities.
Within locality, specimens should be arranged taxonomically,
following Romer's classification.
Due to historical confusion about the appropriate age of mixed assemblages that occur in the Hell Creek Formation, some localities can be found in both the Puercan and Maastrichtian parts of the collection. Eventually this will be fixed, but be sure to double check both areas for specimens.
Because few Rancholabrean sites come from named formations, localities are organized by State, County, and Locality Prefix+Locality Number.
Due to the large number of Wasatchian sites in the Wasatch Fm of Wyoming, these have been further subdivided by county, specifically Lincoln, Sublette, and Sweetwater Cos.