Mount Leura, together with nearby Mount Sugarloaf, forms part of a large extinct volcanic complex known as the Leura Maar. The complex includes a broad shallow maar crater measuring 2.5 km by 1.7 km surrounded by a low tuff ring, inside which are the secondary eruption points of Mount Leura and several smaller unnamed mounds and cones of scoria. These may represent eruptions along a north-south fissure. The walls of the cone are alternating layers of tuff and scoria with numerous blocks and volcanic bombs. Mount Sugarloaf is a perfect conical mound on the southwestern flank of Mount Leura and represents a final stage of activity of the Leura volcano, when a small vent ejected a large volume of lava fragments in a short time, without a change in the direction of the eruption column. This produced a steep, symmetrical, conical mound of volcanic ash, scoria and larger blocks and bombs.