The Admiralty Group of islets consists of eight rocky outcrops within 2 km of the north of Lord Howe Island: Soldier’s Cap, Sugarloaf, Noddy, South Island, Tenth of June, North Rock, Flat Rock and Roach Island. Roach Island is the largest being about 15 ha in area, 800 m long and 86 m high, with a much-photographed 15 m tall tunnel at its northern end. The basalt lava flows are crossed by many dikes. The vegetation consists of grasses, sedges and a few bushes.
- Hutton 1986, p. 81
- Hutton, Ian (1986). Lord Howe Island. Australian Capital Territory: Conservation Press. ISBN 978-0-908198-40-5.