TY - GEN A2 - Feltis, R. D. (Richard D.), 1930- AU - Geological Survey (U.S.), cartographer. CY - Helena, Montana CY - Denver, Colorado L2 - https://purl.fdlp.gov/GPO/gpo135633 LA - English PB - [Department of the Interior, United States Geological Survey, Open-File Services Section, Western Distribution Branch, U.S. Geological Survey] PP - Helena, Montana PP - Denver, Colorado PY - 1982 TI - Map showing altitude of the top of the Fox Hills-Lower Hell Creek aquifer, Montana ER -