Colchester Archaeological Trust

CAT Report 694: summary

An archaeological watching brief at Pinnacle House, 21 St John’s Green, Colchester, Essex - April 2013
by Donald Shimmin (with contributions from -)

Date report completed: May 2013
Location: Pinnacle House, 21 St John’s Green, Colchester, Essex
Map reference(s): TL 9978 2477
File size: 148 kb
Project type: Archaeological watching brief
Significance of the results: *
Keywords: human bone, St John’s abbey

Summary. An archaeological watching brief took place at Pinnacle House, 21 St John’s Green, Colchester, during groundwork in advance of the construction of an extension. The site is located approximately 230 m south of the walled area of Colchester town centre. It lies on the eastern edge of St John’s Green, approximately 30 m north-east of St John’s abbey gatehouse, and is within both a Scheduled Ancient Monument area and a conservation area. The site is situated within the walled precinct of St John’s abbey, and is close to the recently discovered remains of St John’s abbey church. There were no previous records of significant archaeological remains from the site itself, although records from the surrounding area include Roman and medieval burials; remains of medieval monastic and other ecclesiastical buildings; and post-medieval pits, ditches and building remains. The site of the Roman circus lies a couple of hundred metres to the south. Pinnacle House itself dates from about 1830 and is on the local list of historic buildings. The groundworks included a series of narrow trenches for the foundations of the extension, a glazed link between the house and the extension, and a garden wall to the north of the extension. An existing wall was incorporated into the south wall of the extension. The foundation trenches were, with the exception of the trench for the garden wall, dug down to the natural subsoil. The trenches were dug by the contractor using a mini-digger with a toothless trenching bucket, and were monitored by a CAT archaeologist. On health and safety grounds, the recording of the archaeological deposits was done from the modern ground-level looking down into the trenches. The natural subsoil was reached in the foundation trenches for the extension and the glazed link. The natural subsoil consisted of brownish-yellow gravelly sand, sealed in places by thin deposits of pale brown cover loam. In most of the trenches, the natural subsoil was sealed by an extensive, homogeneous, greyish-brown layer. Oyster shells were fairly common in this layer. A small quantity of human bone fragments was recovered during the machine-digging of the foundation trench for the north wall of the extension. The fragments were well-preserved and included lower limb bones, vertebrae, and skull and mandible fragments, probably from one or more adult/adolescent individuals. However, the context of the human bone fragments remained unclear. They probably came from about 1.75 m below the modern ground- level, where further bone fragments were visible in the northern section. It was uncertain whether the fragments came from an in situ burial or whether they were redeposited. No grave cuts were visible and the bone fragments seemed to derive from the greyish-brown layer. The bones were probably medieval in date and belonged to a cemetery associated with St John’s abbey church. Other finds from this layer were sparse, and no securely-stratified dating evidence was recovered. This layer was sealed by dark greyish-brown, modern topsoil. In places there were also thin deposits of modern dump/make-up at or near the modern ground surface. The deposits in the trenches were heavily rooted. Several modern brick foundations were encountered in the trenches. The greyish-brown layer was the most significant archaeological deposit uncovered during the watching brief. However, the limited nature of the investigation made interpretation of this layer difficult and it remains undated. The presence of bands of oyster shells suggests that it accumulated gradually. It was possibly the backfill of a large, shallow pit, which was perhaps dug to extract sand and gravel. Quarry-pits of varying dates, from Roman to modern, have been found elsewhere in the St John’s abbey area. Alternatively the layer could have been accumulation and/or make-up on top of an earlier ground surface. The human bone fragments were reburied in a trench dug for a soakaway in the northern part of the site. No finds were retained.