GEOLEX is a search tool for lithologic and geochronologic unit names and includes more than 16,000 entries. GEOLEX provides information on the original and current description of the unit, the type locality, geologic age, geographic extent, variations in geologic name usage, and publications that have described the unit.
The National Gelogical Map Database is the resource for maps and related data about geology, hazards, earth resources, geophysics, geochemistry, geochronology, paleontology, and marine geology, including GEOLEX, which provides the lexicon of Geologic Names of the United States.
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