Cleft Island, also known as Skull Rock, is a small, rugged,

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

island An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been ...

in the Anser group of islands to the south-west of

Wilsons Promontory Wilsons Promontory is a peninsula that forms the southernmost part of the Australian mainland, located in the state of Victoria (Australia), Victoria. South Point (Wilsons Promontory), South Point at is the southernmost tip of Wilsons Promon ...

Victoria Victoria most commonly refers to: * Queen Victoria (1819–1901), Queen of the United Kingdom and Empress of India * Victoria (state), a state of Australia * Victoria, British Columbia, Canada, a provincial capital * Victoria, Seychelles, the capi ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. The island is within

Wilsons Promontory National Park The Wilsons Promontory National Park, commonly known as Wilsons Prom or The Prom, is a national park in the Gippsland region of Victoria, Australia, located approximately southeast of Melbourne. The national park is the southernmost national ...

. The surrounding waters to the mean high-water mark are within

Wilsons Promontory Marine National Park The Wilsons Promontory Marine National Park is a protected marine national park located in the South Gippsland region of Victoria, Australia. The marine park is situated off the southern tip of Wilsons Promontory and extends along the coastl ...

. It is part of the

Wilsons Promontory Islands Important Bird Area The Wilsons Promontory Islands Important Bird Area comprises a loose cluster of 19 small, granite islands, with a collective area of 658 ha, scattered around Wilsons Promontory in the state of Victoria, south-eastern Australia. The three ...

, identified as such by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

because of its importance for breeding

seabird Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...

s. It is partially hollowed out by ancient waves, creating a cave wide and tall. Only 9 people have ventured into the cavern, finding "old cannon balls left by passing ships practicing their aim". Adventurers had to land on the top of the rock by helicopter, then they shimmied down ropes to gain entrance to the cave. .

References

Islands of Victoria (state) Wilsons Promontory Important Bird Areas of Victoria (state) {{Gippsland-geo-stub