As a result of recent field work, a new lithostratigraphic group is defined on the west coast of James Ross Island, Antarctica. Characterised by comparatively coarse-grained sediments, the Gustav Group is 2300 m thick and has an approximate age range of Barremian-Santonian. Four formations are recognised within the group (the Lagrelius Point, Kotick Point, Whisky Bay and Hidden Lake Formations), and of these, the Whisky Bay Formation is further subdivided into six local members. Type sections are erected for each of these stratigraphic units and representative lithologies and faunas described.