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Federal
U.S. Level III and IV Ecoregions (U.S. EPA)
U.S. Environmental Protection Agency —
This map service displays Level III and Level IV Ecoregions of the United States and was created from ecoregion data obtained from the U.S. Environmental Protection... -
Federal
Mineral Resource Data System (MRDS) Points, U.S. EPA Region 9, 2016, USGS
U.S. Environmental Protection Agency —
Mineral resource occurrence data covering the world, most thoroughly within the U.S. This database contains the records previously provided in the Mineral Resource...