Correlation chart of lower and upper Cretaceous Blackleaf Formation, eastern Pioneer Mountains, southwestern Montana, to Drummond, central-western Montana U.S. Department of the Interior, U.S. Geological Survey ; by T.S. Dyman [and others].
Series Titles:
Miscellaneous investigations series ; map I-2478 Miscellaneous investigations series (Geological Survey (U.S.)) ; map I-2478.