Colchester Archaeological Trust
CAT Report 347: summary
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Roman buildings, the rear face of the Roman town wall and archaeological investigations in Insulas 1a, 1b, 9a and 9b, at the Sixth Form College, North Hill, Colchester, Essex: April 2005-March 2006
by Howard Brooks, Will Clark, Marius Gorniak, Laura Pooley
(with contributions from S Benfield, M Bridge, N Crummy, P Crummy, V Fryer)
Date report completed: 21/01/2009
Location: Colchester town centre, Essex
Map reference(s): TL99302540 (c)
File size: 12 kb kb
Project type: Two watching briefs and an excavation
Significance of the results: **
Keywords: Roman town house, Roman street, ?bath-house, high-quality painted wall-plaster, Roman town wall, Roman interval tower
The grounds of the Sixth Form College occupy a sizeable proportion of the north-west corner of the walled Roman town, including parts of Insulas 1a, 1b, 9a, 9b, 17a and 17b (in fact, Insulas 1a and 9a are wholly within the college grounds).
Archaeological work described here (mainly watching briefs with selected excavation) was carried out in advance of the construction of the new mid site building (Area B here) and in advance of the construction of an access road on its east and north sides (Area A). Pipe trenches to run off water down-slope were also monitored as part of Area A. Services required the Roman town wall to be breached to allow a pipe to pass through it. In advance of this work, and to provide access for the contractors, a deep vertical shaft (Area C) was archaeologically excavated against the inner face of the town wall from modern ground-level to below the base of the wall.
Principal discoveries were as follows. In Insula 1a, there was a large building consisting of surviving in situ masonry wall foundations, robbed-out wall lines, and of tessellated, opus signinum and mosaic floors (Colchester Building 211). Associated finds, principally marble and decorated wall-plaster, indicate that this was a high-status building.
To the north of Building 211 and also in Insula 1a, a separate structure with a timber water channel (Building 212) may have been a room of a bath-house associated with Building 211, or possibly a shrine to a water deity.
In Insula 1b, to the east of Building 211 and Building 212 and across the previously unknown gravel street dividing Insula 1a from Insula 1b, was the south-western corner of another possibly high-status building, with decorated wall-plaster, surviving in situ masonry wall foundations and opus signinum floors (Building 214). The assemblage of decorated wall-plaster from F37/L42, adjacent to Building 214, is important, being painted in imitation of marbles and opus sectile.
The excavation of the shaft against the inner face of the Roman town wall went through the Roman rampart and revealed the construction road below. It also exposed 6.84 m of standing Roman masonry, 3.3 m of which was faced with alternating bands of septaria and Roman brick. Parapet walk level can be inferred at approximately 6.70 m above Roman street level.
Also on the inner face of the Roman town wall, there was a substantial piece of robbed masonry exposed in a pipe trench which is best interpreted as the remains of a previously unknown interval tower.
There appears to have been very little post-Roman activity on the land now occupied by the Sixth Form College. Recent excavation and evaluation work has shown that a substantial depth of topsoil accumulated over the site in this period. The usual interpretation of this soil accumulation, often found in Colchester, is that the land was left open and/or was used for small-scale agriculture or horticulture in the Anglo-Saxon and medieval periods.