Colchester Archaeological Trust

CAT Report 627: summary

An archaeological evaluation by fieldwalking, geophysical survey and trial-trenching at the Northern Growth Area Urban Extension (NGAUE), Colchester, Essex - September-December 2011
by Howard Brooks, Ben Holloway, Dr Tim Dennis (with contributions from Stephen Benfield, Val Fryer)

Date report completed: March 2012
Location: Northern Growth Area Urban Extension (NGAUE), Colchester, Essex
Map reference(s): TL 986 279 (c)
File size: 34,355 kb
Project type: Archaeological evaluation by fieldwalking, geophysical survey and trial-trenching
Significance of the results: **
Keywords: prehistoric, ring-ditch, Roman, ritual pit, medieval, pottery kiln, post-medieval, tile kiln

Summary. In advance of proposed development, an evaluation by geophysical survey, fieldwalking and trial-trenching was carried out on the Northern Growth Area Urban Extension site (NGAUE) in north Colchester. For ease of discussion, NGAUE is split into Project Areas 1-6 (A1-A6). The previous discovery of large quantities of medieval potsherds at separate sites in the parishes of Mile End and Great Horkesley is evidence that a series of separate pottery kilns were in operation here, collectively known as the ‘Mile End’ pottery industry’. The kilns themselves have not been found, but the Colchester Urban Archaeological Database (UAD) and the Essex Historic Environment Record (EHER) record two potential kiln sites in NGAUE. The first, close to A12 Colchester Northern bypass (in A4) may, in fact, have been destroyed by the construction of the A12. The second consists of a group of pits containing ‘wasters’ from medieval pottery production discovered when the old A134 was diverted onto a new route close to Cants Rose Fields (ie, between A1 and A2). This site (NGR TL 987 285) was excavated under the direction of Martin Petchey in 1973, and later published with Paul Drury (Drury and Petchey 1975). Although the kilns were not found on the Petchey site, their inevitable presence somewhere in the vicinity has set the agenda for the archaeological response to much of the northern half of the NGAUE development, and is the basis for the location of geophysical survey and the location of some of the regular grid of trial-trenches. EHER and UAD also record two separate spreads of medieval pottery on fields adjacent to the Petchey site (A1) which may also be connected with the pottery industry. The fieldwalking survey (FWS) was carried out on all available ploughed areas (49.8 ha, in A1-A4). Finds were generally quite thinly spread, but there were three significant groups: an extended scatter of medieval pottery on the fields to the east of the 1973 excavation site (A1, FWS boxes B85, B86/B96, TL 9885 2850); a scatter on the field south of the 1973 excavation site (A2, FWS boxes B72/B73, TL 9875 2818); and one of Roman brick/tile (A3, FWS box D48, TL 9845 2775). The geophysical survey (GS) was carried out by Dr Tim Dennis on a 4.5ha area around the 1973 excavation site (A1, and A2), and on a 1.44ha area on the potential kiln site close to the A12 (A4). This survey located a number of anomalies, but none of them were of the strength and intensity likely to be a kiln site. The trial-trenching evaluation (TTE) covered 64ha in A1-A6, and consisted of 237 trenches. It had two aims: to test some of concentrations of fieldwalking finds and geophysical survey anomalies, and to provide a broad evaluation coverage of NGAUE. The trenching of the GS anomalies (A1/A2, A4) was generally inconclusive – no kiln sites were found, although a number of anomalies were located which were later trial-trenched. The trenching of significant FWS scatters The trenching of the significant scatter of medieval pottery in A1 did not reveal a kiln site, but did identify areas of burning and gravel surface which are likely to be associated with the kilns (T242, T244: TL 9885 2850). The southern end of the same scatter produced only low quantities of medieval pottery: T248, T249. Trenching of the significant scatter in A2 did not produce any significant results. Trenching of the significant FWS scatter of Roman brick/tile in A3 (FWS box D48, T159: NGR TL 9845 2775) revealed rows of post-medieval bricks set in clay, burnt debris and layers of broken tiles. Given that this field is named ‘Kiln Field’, and that (retrospectively) the trench position coincides with an area of burnt ground identifiable on Google Earth), the finds in T159 are best explained as part of a structure adjacent to a post-medieval kiln. The size of the patch of burnt ground on Google Earth is approximately 40m across. The presence of Roman tile on the field surface is unexplained, unless it had been deliberately incorporated into the structure of the post-medieval kiln. Trenching results on other parts of NGAUE Significant trenching results in other parts of NGAUE are as follows: In A2, T64 exposed a prehistoric ditch which may be part of an Iron Age ring-ditch of the type commonly found surrounding timber structures. In other words, this may be an Iron Age house site. In A5, T196 revealed a pit containing fragments from sixteen smashed Roman pots mixed in with cremated human bone. This may have been a Roman cremation burial, but the number of separate pots involved makes a more general ‘ritual’ interpretation attractive. It is unlikely that this was an isolated feature, and other Roman burial/ritual activity may be located nearby. In A6, T237 exposed a ditch which contained over 1kg of Late Iron Age or early Roman pottery. This must come from a local (but unknown) Roman site, which may be close to T237.