Web map tile service specification published by the Open Geospatial Consortium

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Maps of hydrothermal alteration in the Basin and Range province of the US

Maps and data showing the geographic distribution of surficial minerals likely produced by hydrothermal alteration, which may indicate areas permissive of gold and copper mineral deposits.

State geologic map compilation

Digital geologic maps of the US states with consistent lithology, age, GIS database structure, and format