well is a floor hatch, which would have allowed food to be transferred directly from the kitchen to a servery above. A room in the square tower to the west, possibly the lord's bedroom, has holes in the ceiling to allow smoke from braziers to escape. The more ruined west round tower probably contained another hall, with chambers above and storage below. In the 17th century, the top of the main round tower was lowered and remodelled to form a gun platform. Only fragments of the rest of the 13th-century castle remain. A fourth tower, where the Ruthven lodging now stands, may have completed the "cluster keep". Bases of round towers at the south-east and north-east corners of the castle are visible below the later walls. Parts of the north-west wall are 13th-century work, as is the blocked postern in the basement of the east range. The overall plan of the castle, however, was not greatly changed through later rebuilding work. Dirleton is the earliest dated example in Scotland of a castle with round towers that project beyond the curtain wall, as opposed to those at Dunstaffnage, for example, where the towers are contained within the walls. This new form was subsequently used in other 13th-century Scottish castles, including Bothwell and Kildrummy. The east range and gatehouse The gatehouse, kitchens, and east range were built by the Haliburtons in the 14th and 15th centuries. The gatehouse, built in the 14th century to the east of the keep, is similar to the one at nearby Tantallon Castle. It is fronted by a high, pointed arch, formerly with bartizans, small round turrets, at the top. The gate was protected by a drawbridge over the outer ditch, a portcullis, and three sets of doors. Guard rooms open off the entrance passage, and a round opening in the roof, known as a "murder hole", allowed defenders to drop objects on to any attacker who breached the outer gate. The large kitchens occupy the south-east angle of the castle. The high main kitchen has two wide fireplaces for cooking, and a circular vent in the vaulted ceiling. Hatches in the floor give access to a well ( deep) and cellars below. The adjacent passage linked the kitchen to the hall in the east range. The east range itself runs the length of the east side of the castle, and originally comprised a large hall, with