EDO4352 - Dorchester Prison Excavations, 1975, Trench 11

The site of the Prison Governor's house and a small extension to the prison were totally excavated for the Dorchester Excavation Committee in 1975. The large area to the west of the Prison, which is to be redeveloped in the immediate future, was trial-trenched as far a financial resources and standing features would allow. 260 sq. m were stripped to the natural chalk. A total of 11 trenches were excavated by hand and by machine. The earliest features on the site were three large slots, filled with chalk. They did not appear to be construction slots or drainiage gullies. One of these was cut by a large pit containing material of Flavian date. Three pits of this date, also filled with chalk, were excavated. Three apparently Roman post-holes and an occupation layer were excavated north of the early features. In the eastern trenches, vestiges of an extensive layer of rubble, probabaly of the 2nd century, were found. The earliest phase of the medieval Castle ditch was sectioned by hand. It had been dug to a depth of of 4.4m. This had been backfilled, and subsequently a smaller ditch was dug slightly to the east. After some silt had accumulated, this ditch was slighted. No remains of the bank were found, the area having been levelled in the 17th or 18th century. A small irregular curving ditch was excavated on the lip of the scarp leading down to the river. It seems to follow the line of one of the earthworks on Hutchin's plan of 1772, and may belong to the Civil War. Spreads of chalk found in several of the trial trenches probabaly relate to the lime kiln known to have existed on this site by the 18th century. Trench 11contained a wide gully like slot cut into the chalk, running E-W, 1.3-1.55m wide and 0.5m deep with a U-profile and a flat base, containing mid 1st century material. This slot was cut by a later 1st century pit and the medieval castle ditch. The ends of two similar slots were found on the south side of the trench. They terminated before reaching the first slot and seem to respect it. The slots are unlikely to be for drainage on the chalk and are too large for construction purposes. The medieval castle ditch was from phase 2 of the defences, had a V-profile and measured 3.1m wide and 1.25m deep. It was discernably of two phases in this trench.