No current usage?
(†Midway Hill Basalt (WY) considered abandoned? Uncertain if used by the WY Geol. Survey. Not used by the USGS.)
Tertiary
Pliocene
Named because of its position midway between Overhanging Cliff and the great basalt butte at Rainy Lake, northern Yellowstone Park, WY (Howard, 1937).
Yellowstone province
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).