The Fauna of the Mid-Atlantic Islands

Tristan da Cunha, Nightingale, Inaccessible, and Gough Islands are the only Atlantic oceanic islands lying within the southern cold temperate zone. Their relative positions, and the situation of the group as a whole, are shown in figure 49. All of them are volcanic, and probably initially of Tertiary age (Dunne 1941; Le Maitre 1959). There is no historic record of activity but Tristan retains a central cone and well-preserved lateral cinder cones which appear of recent origin. Undated ash bands occur in the peats of this island, and a small, rather broken cone (Edinburgh Peak) on Gough Island may have been the source of an ash band in peat dated by the radiocarbon method as 2345 ± 130 years old (Hafsten, this Discussion). The other two islands show no trace of recent volcanicity. All the members of the group rise steeply from deep water, and there is no sign of previous land links between them