Intent to name [informally?] not stated. Probably named for small drainage basin in southeastern Owyhee Co, ID, Snake River basin. [May have been named in unpublished thesis (Bernt, J., 1982, Univ of ID)]. No type locality designated in this report. Exposed in Cottonwood Creek and Rattlesnake Draw drainages in southeastern part of map area. Unit is a hard, devitrified, brown to grayish-red rhyolitic tuff; contains phenocrysts of biotite, black opaques and zircon; locally contains relict shards and flattened pumice? fragments; small partially filled lithophysae are common. No thickness given. Overlies Cedar Canyon tuff (new) of Bieroth volcanics (redescribed); underlies Cougar Point Tuff and perhaps Whiskey Draw rhyolite (first used). Geologic map. Not known if unit was erupted from a local volcanic center or if it is an early unit from Bruneau-Jarbidge eruptive center and, therefore, would be assigned to Cougar Point Tuff. Miocene? age.

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