The spatial databases represent the original content of 43 published geologic maps, provide normalized map unit descriptions, and provide additional information and interpretation not in the original reports.

Geologic map unit and lithologic descriptions used in Open File Report 2005-1235, with extensive bibliographic references to geologic literature that could not be included in the spatial database.

Detailed descriptions of more than 200 mineral districts, mines, and mineral occurrences (deposits, prospects, and showings) within the United States that are reported to contain substantial enrichment of rare earth elements.

Reanalysis of existing samples provides more precise and accurate geochemical data because newer methods can be used. Stable isotopes of lead were also included. Data are provided in Microsoft Access, CSV, and shapefile formats.