The outer bailey was roughly rectangular, with thick walls faced in sandstone and infilled with rubble. The walls, parts of which still remain, contain a number of D-shaped towers, an innovation in English castles at that time. The towers allowed defenders to shoot across the walls as well as forwards, and their open-backed design meant that they would not offer cover to any attackers who gained access to the outer bailey. The inner bailey was situated on the rocky summit at the western end of the crag.