Event/Activity EPM16 - East Ravelin

An archaeological evaluation was undertaken by Portsmouth Museum Service in August 1972 prior to the construction of a new library for Portsmouth Polytechnic. The area of investigation had previously been occupied by the town defences, principally the East Ravelin. The ravelin had been constructed during a major remodelling of the defences during the 18th century by Desmaretz, and had been built over an earlier position constructed by De Gomme in the 1660s-1680s. The defences were demolished post-1860. The area where the evaluation took place was not developed. The evaluation was restricted by time constraints, and therefore trenches were excavated in areas thought to have the best archaeological potential. A series of eight trenches were excavated in order to investigate the presence/preservation of the ravelin. Trench I (located approximately SZ63619967) measured 25m long x 1m wide and was cut from the north face of Town Mount Bastion in order to establish the exact location of the remaining masonry and its condition, and examine the backfilled moat prior to excavations in the area of the East Ravelin. Trench 2 measured 30m long x 1m wide (located approximately SZ63699958) and was cut from within the ravelin eastwards across the moat and into the counterscarp and covert way. Trench 3 (located approximately SZ63699958), 12m long, was excavated in order to examine the infill of the moat in more detail by the east side of the ravelin face. Trench 4 (located approximately SZ63719962) was triangular, and cut to locate the salient apex of the ravelin. Trench 5 ((located approximately SZ63719962) was 10m long and was excavated to examine the infill of the moat near the apex of the ravelin, from the counterscarp wall to the centre of the moat. Trench 6 (located approximately 63659964) was 6m long and excavated to examine the covert way beyond the moat and north of the ravelin. Trench 7 (located approximately SZ63769959) was 5m long and was excavated to the east of the ravelin beyond the glacis to establish stratification detail and ascertain whether there were any remaining fortificational features from earlier periods. Trench 8 (located approximately SZ63769955) was 5m long. Due to the proximity of large trees and shrubs it was not possible to pursue excavations in trenches 7 and 8 in the area north of the ravelin. The excavations revealed how the 18th century system had been imposed on the 17th century defences, principally with the cutting of a foundation trench for the main salient-face masonry into the remaining bulk of a previous gun platform. It also showed the extent of the demolition of the defences and the infilling of the moat.