island, including extinct penguin species (such as Palaeeudyptes klekowskii and Archaeospheniscus wimani), various species in the bivalvia class and various types of flora and fauna, including a frog. A fossil marsupial of the extinct family Polydolopidae was found on Seymour Island in 1982. This was the first evidence of land mammals having lived in Antarctica. Further fossils have subsequently been found, including members of the marsupial orders Didelphimorphia (opossum) and Microbiotheria, as well as ungulates and a member of the enigmatic extinct order Gondwanatheria, possibly Sudamerica ameghinoi. IUGS geological heritage site In respect of the site being the 'most representative high latitude K-Pg boundary location and one of the most significant and best exposed globally' the 'Cretaceous-Paleogene Transition at Seymour (Marambio) Island' was included by the International Union of Geological Sciences (IUGS) in its assemblage of 100 'geological heritage sites' around the world in a listing published in October 2022. The organisation defines an 'IUGS Geological Heritage Site' as 'a key place with geological elements and/or processes of international scientific relevance, used as a reference, and/or with a substantial contribution to the development of geological sciences through history.' Features Bertodano Bay Cross Valley Fossil Bight Larga Valley Penguin Bight See also Snow Hill Island Formation Composite Antarctic Gazetteer List of Antarctic islands south of 60° S SCAR Territorial claims in Antarctica References Islands of the James Ross Island group Argentine Antarctica British Antarctic Territory Chilean Antarctic Territory Cenozoic Antarctica First 100 IUGS Geological Heritage Sites Historic Sites and Monuments of Antarctica Paleontological sites of Antarctica