Geologic map of the Frank Island quadrangle, Yellowstone National Park, Wyoming
No abstract available.
Wyoming↗
Geology topics
William R. Keefer
Publications and source records attributed to William R. Keefer.
Radiometric ages of intrusive rocks in the Little Belt Mountains, Montana
Radiometric ages indicate that most, if not all, of the major intrusions in the Little Belt Mountains, central Montana, were emplaced during the Eocene epoch, between 48 and 54 m.y. ago. In the Hughesville area, igneous activity continued, or was episodic until 42 m.y. ago. As a result of the continued igneous activity, radiometric ages in the Hughesville area can be interpreted either as primary ages or as reset ages.
Montana↗
Preliminary geologic map of the Neihart (7 1/2') quadrangle, Cascade and Judith Basin Counties, Montana
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Open-File Report↗