The feature is 11 nautical miles (20 km; 13 mi) long and 5 nautical miles (9.3 km; 5.8 mi) wide and projects southward into the northern part of the Larsen Ice Shelf west of Larsen Inlet.

A ridge trending north-northwest – south-southeast and rising to 855 metres (2,805 ft) high southwest of Nodwell Peaks.

A nunatak rising to 935 metres (3,068 ft) high, 1.3 nautical miles (2.4 km; 1.5 mi) south-southeast of Nodwell Peaks.

The gap provides a coastal route which avoids a long detour around Sobral Peninsula Mapped from surveys by FIDS (1960–61).

Named by UK-APC after the Phoenix Manufacturing Company of Eau Claire, Wisconsin, which started in 1906-07 to design and build steam "locomotive sleds" for hauling logs over ice and snow, probably the earliest successful vehicles of their type.

Named by the UK-APC after Geoffrey W. Farquharson, BAS geologist who worked in this area in the 1979–80 and 1980-81 field seasons.

A hill (505 metres (1,657 ft) high) on the eastern edge of the central mountain mass of Sobral Peninsula.

Named by the UK-APC for Richard D. Hamer, BAS geologist, Rothera Station, 1978–79 and 1980–81, who worked in the area.