Columbia subject headings:
Geochemical prospecting--Arkansas--Maps.
Geochemical prospecting--Missouri--Maps.
Geology--Arkansas--Maps.
Geology--Missouri--Maps.
Geomagnetism--Arkansas--Maps.
Geomagnetism--Missouri--Maps.
Maps.
Harvard subject headings:
Geochemical prospecting--Arkansas--Maps.
Geochemical prospecting--Missouri--Maps.
Geology--Arkansas--Maps.
Geology--Missouri--Maps.
Geomagnetism--Arkansas--Maps.
Geomagnetism--Missouri--Maps.
Princeton subject headings: