Immediately south of the upper Taylor glacier lies a small ice-free area including three minor dry valleys provisionally named the Arena, Beacon, and Turnabout. The rocks exposed are Beacon sediments intruded by dolerite sills and dykes. Three lithological members are recognized in the sediments. Two petrographically distinct types of dolerite are present. Glacial and post-glacial erosion has produced a land form controlled by the lithology and structural relations of the sediments and dolerite.