An archaeological evaluation at the Mercury Flats, Balkerne Gardens, Colchester, Essex: July-August 2005

This site lies in insula 17 of the Roman town just a few metres away from the west gate (Balkerne Gate) that gave access to the main Roman route to London (Londinium) via Chelmsford (Caesaromagus). It is proposed to demolish an existing building, and rebuild on the same site. The archaeological evaluation had two main aims: first, to measure the position of the highest significant archaeological deposits in relation to modern ground level; second, to assess their date, importance, and condition. Five evaluation trenches were cut, four to the north of the present Mercury Flats, and one to the south (ie on the Mecury Theatre side). All five trenches showed that the highest siginficant deposits were Roman in date, and lay at (no higher than) 1.50m below modern ground on the south side of the site, and between 0.70-1.00m below modern ground on the north side of the site. In terms of absolute heights AOD, the top of the Roman deposits was below 31.38 on the south side of the site, and between 31.62m and 31.97m AOD on the north side. As well as a number of modern, post-medieval and medieval features and layers the archaeological remains exposed included two in situ Roman walls (one partially robbed), a Roman mortared structure (either a floor or a wall), several Roman floor and dump layers and a complete Roman pot probably buried as a foundation deposit. A large quantity of Roman material (brick and tile, pottery, animal bone, etc) was recovered from the site including three late Roman coins.