Middle Saxon Iron Smelting Furnaces and other Sites Along the wing to Peterborough Pipeline: Archaeological Evaluation an Excavation

Between April and September of 1997 a field evaluation as conducted by Cambridgeshire County Council's Archaeological Field Unit (AFU) in advance of construction of a replacement water trunk main between Duddington in Northamptonshire (SK 989/004) and Chesterton, to the West of Peterborough, Cambridgeshire (TL 127/945). The total length of the route was 20.7 km and the width of the easement was in general 30m. The work was commissioned by Anglian Water Services Ltd. and was carried out in accordance with a design brief provided by the Cambridgeshire County Archaeology Office - Development Control (Kaner 1997) and by Northamptonshire Heritage (Kidd 1997)

Following an archaeological desktop assessment, also carried out by the AFU in March and April, 1997, nine areas were selected as having high archaeological potential. For each of these areas a series of non-intrusive evaluation techniques were proposed for the deployment in advance of test-pitting or trial trenching. In addition, the entire easement was to be fieldwalked.

Near Bonemills Farm, Wittering (TF 0475/0153), remains of two iron-smelting furnaces and of a third feature which was probably a smithing hearth were discovered. These were fully excavated in advance of their destruction by the pipeline.

The two furnaces were of a asimilar type, consisting of sub-oval pits about 2.2m long 0.6m wide and 0.15m deep. There was evidence of slag-tapping, with thick flows of top slag remaining in situ from the last firing. The probable smithing hearth was different, consisting of a circular pit about 0.60m in diameter and 0.33 deep. The site had been heavily ploughed and nothing appears to have remained of the furnace or hearth superstructure. Other features nearby contained burnt iron ore and charcoal and were probably Ore-roasting pits. Metalworking residues from the smithing hearth suggested it had been used for primary smithing of the bloom and there was no evidence of artefact manufacture on the site.

Charcoal from one of the slag-tapping furnaces gave a radiocarbon date of 1350+/- 80 BP, cal AD575 to 875 (2 sigma, 95% probability). That from the probable smithing hearth gave a date of 1230 +/- 50 BP, cal AD680 to 905 and cal AD920 to 950 (2 sigma, 95% probability)

No other new sites were located outside the areas of high potential already identified. Even within these areas, results were mostly disappointing, with few archaeological features being found. Problems with access to the route delayed fieldwalking until crop growth was well advanced, and this also affected the geophysical and metal detector surveys. The conditions under which subsequent archaeological work took place may also have affected the results. Construction work associated with an earlier pipeline along the same route has also destroyed archaeological remains in may places.