Monument record 8207/3 - The Roman East Ditch to the rear of No 13 Frodsham Street

Archaeological investigations carried out in a car park to the rear of No 9-13 Frodsham Street in 1966 uncovered a series of features attributed to the Roman fortress defences. Although a comprehensive account of the excavation has not been published, a draft article details the Roman evidence. Several phases of activity could be identified suggesting a series of at least five re-cuts of the ditch throughout the Roman period, no absolute dating was recovered, however and the phasing is based on stratigraphy.(1)

The excavations consisted of six trenches excavated in a former car park surrounding the then extant buildings. Archaeological evidence of the defences was encountered in trench 1 in the north west corner of the site abutting the above ground Roman wall at the former Drum Tower (CHER 8207/3) and in trench 2 in the south west corner of the site close to the medieval city wall (CHER 8207/4). (1)

The first phase of activity dates to the late first century and consists of traces of the primary cut of the defensive ditch in trench 1, although later truncation had significantly affected its survival. The centre line of the ditch was encountered approximately 2.6m in advance of the Roman wall at a depth of 1.30m below contemporary ground level. In profile it appeared to be V shaped with a total width of 4.20m.(1)

The second phase of activity consists of the secondary cut towards the end of the first century creating a wider and deeper ditch. The centre line of the ditch was encountered approximately 3.85m in advance of the Roman wall. Although accurate dimensions of the ditch could not be obtained, it was estimated to be 5.5m in width. (1)

The third phase dates to the beginning of the second century and is characterised by another re-cutting of the ditch. In trench 1 the upper portions of the ditch had been somewhat truncated although the base remained largely intact. The third phase ditch appeared to be a near perfect V shaped ditch 3.40m deep with an overall width of 7.95m tapering to a sharp point at its base. Its centre line was 5.70m from the fortress wall. (1)

The fourth phase of activity dates to the early second to mid third century and consisted of a period of silting within the ditch. In trench 1 several layers were identified consisting of a primary fill of clean silty sand 0.30m thick over which was a 0.60m thick layer of clay and sand. A third fill of brown or red clay rose to within 1.10m of the contemporary ground surface. (1)

The rampart was separated from a substantial outer ditch by a flat area called a berm. The berm was about 1.8m wide and the primary ditch about 3m wide by 1.5m deep. At a later date the defences were further strengthened by the insertion of a stone revetment wall laid in regular courses each about 0.30m high against the outer face of the rampart. This measured about 1.5m wide by about 4.75m to wall walk level and was again surmounted by stone breastwork. The ditch was widened and deepened, perhaps up to 7m by 3m, although re-cutting has made the dimensions difficult to measure.

Anon, 1967, Abstract of Proceedings (Article in Journal). SCH5888.

<1> Chester Archaeology, 1966, Site notes for excavations at Frodsham Street Car Park, Chester (Unpublished Report). SCH6631.

<2> Earthworks Archaeological Services, 2011, Proposed New Market Hall at Frodsham Street Car Park, Chester: Archaeological Desk Based Assessment, R3087 (Client Report). SCH5465.