New Bastion, including part of the counterscarp wall

An 1850s/60s military bastion, including the main bastion wall, and part of the counterscarp wall. Excluded from the listing are the mid-C20 set of stone steps leading from the top of the bastion down part of the east wall to the ditch below, the mid-C20 metal vehicular entrance gates in the counterscarp, and the C20 brick buildings built within the bastion ditch. The truncated and partially rebuilt part of the southern counterscarp wall is also excluded. MATERIALS: Plymouth-limestone ashlar scarp wall with a rubble-limestone counterscarp wall. PLAN: an angular bastion wall, facing toward the east and south, with a parallel counterscarp wall. DESCRIPTION: an ashlar-faced scarp wall topped by a rolled cordon. The wall is abutted and overlain to the north-west by the rubble-stone wall of the new lines. The southern side of the rampart includes a set of musket loops overlooking the approaches to the Old Gun Wharf. The rampart is topped by an earth bank that is partially lined on the interior of the bastion by a low stone rampart. A rectangular expense magazine projects to the south-west from the centre of the eastern bastion wall. It is entered via a brick-arched entrance on the north side of the magazine, leading into a brick-vaulted chamber. The bastion became part of the gardens to Admiralty House which has led to minor adaptations to the internal bastion wall. On the exterior of the bastion is part of the counterscarp wall which survives around the south-east corner of the bastion. It is constructed of rubble stone. Its western flank was truncated and largely rebuilt due to the construction of the mid-C20 Maritime Headquarters Bunker.