The summit of Great Dodd is a smooth, grassy, rounded dome, like its two southern neighbours, Watson's Dodd and Stybarrow Dodd. Together, these three are sometimes called ‘The Three Dodds'. These three are made of volcanic rocks of the Borrowdale Volcanic Group, and the tops of all three are covered by the same sheet of rock, which was formed in a series of huge volcanic explosions accompanying the formation of a volcanic caldera about 450 million years ago.