Colchester Archaeological Trust

CAT Report 184: summary

An archaeological evaluation by fieldwalking and geophysical survey at Colchester Garrison PFI site, Colchester, Essex: Janary-March 2002
by Brooks, H (with contributions from Dennis, Dr T)

Date report completed: 17/05/2002
Location: Garrison, Colchester, Essex
Map reference(s): TL990233
File size: 16452 kb
Project type: Field-walking survey, Geophysical survey
Significance of the results: *
Keywords: Prehistoric flint, Iron Age, Bronze Age, medieval, post-medieval, ceramic building materials, geophysical survey, cropmarks, trackway/droveway, prehistoric field ditches

Summary. A fieldwalking evaluation was conducted over a 62 hectare area of land which coincides with the arable areas of the Colchester Garrison PFI site in Colchester, Essex. With the exception of large quantities of peg-tile (a result of manuring operations), only three classes of archaeological material were found in any quantity: burnt flint (prehistoric), Roman tile, and post-medieval pottery. The Essex fieldwalking methodology defines an archaeological site (or 'significant scatter') as two adjacent 20-metre boxes whose weight of finds is above +2 standard deviations above the mean. There were three such significant clusters of Roman tile, but none of any other materials. Apart from the significant scatters, there were also low-density spreads of struck flints, burnt flints and Roman tile, indicating periods of prehistoric and Roman activity. The relative concentrations of Roman tile are unlikely to indicate the precise position(s) of Roman buildings but probably reflect scatters resulting from the manuring of fields using material collected and stored at or in the immediate vicinity of Roman buildings. The geophysical survey was undertaken concurrently with the fieldwalking. There were some instances where 'anomalies' detected by the geophysical survey were quite clearly archaeological features already known as cropmarks. This was particularly so of a number of double-ditched trackways. Where there was a direct correlation, the cropmark plots were corrected to the anomaly positions. In other cases, geophysical anomalies probably represent previously unknown archaeological features, perhaps field-boundaries, which add further detail to the picture of the late prehistoric and Roman landscape now being built up by these various archaeological survey techniques.