Named as a formation for Kenney Creek, Lemhi Co, ID in the Idaho Mountains province. No type locality designated. Is exposed in hills on both sides of Lemhi River; is most widespread in foothills bordering Beaverhead Range. In general, confined to Lemhi Valley, Lemhi Co, ID. Consists largely of beds of shale and to lesser extent of sandstone, conglomerate, and locally tuff and bentonite. Conglomerate beds are scattered, generally thin, and not very persistent. Shale is light-colored and somewhat sandy. Beds of sandstone are white or pale buff. Thickness not known, but several hundreds of feet of beds can be inferred from distribution of outcrops. Overlies Challis volcanics; underlies the Carmen formation. Index map. Is of probable late Oligocene age based on its stratigraphic position.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Age changed from late Oligocene or early Miocene to probably late Oligocene based on its position above the Eocene Challis Volcanics and below the Miocene Geertson and Kirtley Formations. Geologic map; cross sections. Lemhi Co is in the Idaho Mountains province. More than 500 ft estimated to be present in report area.

Source: GNU records (USGS DDS-6; Denver GNULEX).

Cannot be recognized and consistently mapped in its type area, or in any area adjacent in the Lemhi Valley, Lemhi Co, ID, Idaho Mountains province. Name abandoned.

Source: GNU records (USGS DDS-6; Denver GNULEX).