[3] The cliff line which includes Cape Gantheaume consists of a metamorphic rock belonging to the Kanmantoo group bedrock called Middleton Sandstone.

The heath has a cover of 70 to 80% with exception of the immediate cliff edge and grows on soils varying from shallow sand to sheet limestone where plants will form mats over the bare rock surface.

[6] Cape Gantheaume and the coast immediately to its east is notable as a haul out area and breeding colony for New Zealand fur seals.

[8] Cape Gantheaume was discovered and named after Vice Admiral Honoré Joseph Antoine Ganteaume (1755–1818) by the Baudin expedition to Australia during 1803.

[14] As of 2012, the waters surrounding its shores are part of a habitat protection zone located within the boundaries of the Southern Kangaroo Island Marine Park.