geologic maps  search
BTmaps
 .geologic maps
SNBefore 1978, also search maps AND geologic.
Geologic Maps (category)  search
SNGeologic maps, GeoRef category code 14, is one of thirty categories used to classify documents in GeoRef. Each reference in GeoRef is assigned one or more categories. Categories can be used, in addition to Terms, to refine searches (See List A.).