They have dark, weathered charnockite bedrock that is littered with light-colored quartz-rich, granitic gneiss glacial erratics.

During the late Quaternary the ice sheet thickened by about 160 metres (520 ft) at the Brown Range.

An isolated, sharp, serrated ridge situated 1 mile (1.6 km) south of Mount Twintop in the Framnes Mountains, Mac.

The two main peaks in this range were plotted by Norwegian cartographers from air photographs taken by the Lars Christensen Expedition (1936).

Gordon Peak was used as an unoccupied Trigonometrical station by Max J. Corry, surveyor at Mawson in 1965.