Geology
The Farnes are resistant igneous Dolerite outcrops. These would originally have been connected to the mainland and surrounded by areas of less resistant limestone. Through a combination of erosion of the weaker surrounding rock, and sea level rise following the last ice age, the Farnes were left as islands. Because of the way the rock is fissured, Dolerite forms strong columns. This gives the islands their steep, in places vertical cliffs, and the sea around the islands is scattered with stacks up to 20 metres (66 feet) high. Many of the small islands are bare rock, but the larger islands have a layer of clay subsoil and peat soil supporting vegetation. The rock strata slopes slightly upwards to the south, giving the highest cliffs on the south and some beaches to the north.
Read more about this topic: Farne Islands