Archaeological investigations in 2011/11 found substantial buried remains associated with the ravelin that formerly protected the south-west approaches to the fort. The ravelin, which could not be fully excavated, comprised a diamond shaped structure with internal walls that defined rooms designed for musketry defence. The ravelin was orignally at least a two storey structure although it was much truncated. There were a number of internal features including doorways, stairs and possible chimneys.