Named for exposures in valley of Galena Creek west of Game Lodge Hotel, east of Custer in southeast part of Black Hills, Custer Co, SD in the Midcontinent region. No type locality designated. Intrudes pre-Cambrian sedimentary rocks. Cut by dikes of Harney Peak granite. Age relative to the newly named Little Elk gneissoid granite uncertain. Is a gray, fine-grained (crystals 1 to 3 mm in diameter) biotite granite--essentially quartz, feldspars, and biotite. Has a hypautomorphic-equigranular texture with a plane and linear parallel structure due to orientation of biotite and oligoclase. Reaction rims occur around minerals enclosed in biotite and oligoclase; the outer band is green and the inner band is lighter color. Biotite and oligoclase were the first to crystallize. Of pre-Cambrian age.

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