The Ross Orogeny in the Transantarctic Mountains was a major phase of deformation and metamorphism in early Palaeozoic time (c. 500 Ma) and took place along the Pacific margin of the East Antarctic continental shield or “craton”. It was also associated with intrusion of granites. This buttress, well-known from its association with one of Shackleton’s 1908 camps on Beardmore Glacier, comprises smooth glacially eroded granite from this Orogeny.