Colchester Archaeological Trust
CAT Report 569: summary
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An archaeological watching brief on the excavation of foundations for an art installation, Lower Castle Park, Colchester, Essex: September 2010
by Adam Wightman
Date report completed: September 2010
Location: Lower Castle Park, Colchester, Essex
Map reference(s): TL 99822 25600 (c)
File size: 146 kb
Project type: Watching brief
Significance of the results:
CAT monitored the excavation of foundation trenches for a temporary art installation in Lower Castle Park, Colchester, Essex. The site work comprised the construction of a concrete foundation of four linked concrete pads (LPA no F/COL/10/1737). The installation is located 45m north of the Roman town wall, 60m south of the River Colne, and 30m east of the boating lake. The turf was removed from the excavation area prior to the excavation of the 600mm-deep foundation trenches. Modern finds (ie plastic bottle tops) were observed in the upper part of the medium grey/brown topsoil layer L1), and oyster shell, slate, Roman CBM and peg-tile were recovered from throughout the layer. A cluster of nails dating to the late post-medieval to modern period was also identified in the northern foundation trench. The topsoil layer was 160mm deep including the turf.
Beneath the topsoil was alluvial silty clay roughly 400mm deep, containing very rare inclusions of stone, charcoal and CBM. Occasional Roman CBM fragments were recovered (a selection of which were retained), as well as eight abraded sherds of Roman pottery. Peg-tile fragments and some very well-preserved animal bones, derived from domesticates (some exhibiting butchery marks) and a deer, were also recovered. It is possible that this layer represents alluvial build-up in a flood plain/meadow environment and that the finds were well stratified. However, it was not possible to say for certain as work was undertaken under watching brief conditions and many of the finds were recovered from the upcast soil.
Two archaeological features were identified, both in the southern foundation trench. F1 contained frequent stones, sand, and brick and tile fragments. Based on the profile observed in the eastern trench edge, F1 appeared to be a shallow ditch. The southern edge of F1 was beyond the southern limit of excavation. Frequent fragments of Roman brick and tile were recovered from the feature (a selection of which were retained). Of particular interest was a large fragment of Mammata, tile which are not particularly common from excavations in Colchester. A few fragments of peg-tile were also recovered from the upper fill of the feature. The feature is visible on Google Earth as an east-west orientated linear that joins a north-south linear to the east. An examination of historic maps of Colchester show these features to be old field boundaries or drainage ditches which divided the land in the post-medieval period and possibly earlier. They have been subsequently infilled, with considerable Roman material incorporated in the infill material.
A square-shaped pit was identified beneath F1, and its northern edge appeared to be beyond the southern limit of excavation. The pit contained frequent large building material fragments in a mortar-rich fill. The building materials consisted of Roman brick, septaria and worked limestone. Two fragments of modern pottery were recovered from the vicinity of this feature and are either associated with F1 or, more likely, with F2. As such, it is probable that the building materials were placed into the pit after it had been dug into the base of the boundary/drainage ditch F1.