NHER 66859 (Monument record) - Medieval saltern

September 2015. Desk-based Assessment.
Assessment of proposed development site.
See report (S1) for further details.
P. Watkins (HES), 15 April 2023.

April-May 2021. Trial Trenching and Excavation.
Evaluation of proposed development site followed by targeted excavation.
The five trial trenches excavated revealed a number of features likely to have been associated with medieval salt production. Several substantial channels were also recorded, one of which appears to correspond with a sinuous drainage feature that was still extant in the 19th century. The most complex group of remains was exposed in the central part of the site, adjacent to one of the numerous probable medieval saltern mounds visible as earthworks on aerial photographs of this area (part of a group of three such features recorded as NHER 27901). These remains were the focus of a small excavation undertaken soon after the completion of the trial trenching.
Evidence for earlier activity on the site included a small assemblage of prehistoric worked flints, all of which were recovered from a feature recorded as a possible tank that also contained a number of burnt flints. This flints include a potentially Early Neolithic blade, along with a number of more irregular pieces of probable later prehistoric date. The site also produced two sherds of Late Saxon pottery, providing further evidence that industrial activity had begun in this area by at least the 11th century.
The bulk of the excavated features were though likely to be associated with a medieval salt industry. As at other sites of the period it appears that salt was being produced by boiling down a brine solution created by washing and filtering salt-impregnated silts and sands scraped up from the nearby marshes or foreshore. The saltern mounds represent the accumulated waste from this activity. Both elements of the process are represented at this site, with a number of filtration tanks identified, as well as several hearth-type structures that would have been used to heat the brine. Various successive phases of activity appear to be represented with several of the overs constructed within the earliest group of tanks. The site was then seemingly abandoned for a period before a further series of tanks were cut through the silt layers that had accumulated over the earlier remains. A mix of high medieval and late medieval pottery was recovered, with the latest material being Dutch-type redware of 15th- to 17th-century date, some of which came from the one of the deposits overlying the main group of ovens. At least one of these hearths was built using bricks broadly datable as late 13th to 16th-century. These brick are of varying size and they were not carefully formed. Samples taken from the medieval features produced a range of charred cereal grains, including examples of hulled six-row barley, bread wheat, common oat and rye. Chaff was also noted as well as weed seeds, suggesting that crop processing waste was probably being used as fuel. Other plant macrofossils amongst the charred remains suggest that peat was also being burnt. Uncharred, waterlogged plant remains suggested that cereal straw was possibly being used as part of the filtration process.
It is unclear at present whether any deposits associated the saltern mount were identified.
The site also produced a small assemblage of fired clay likely to represent fragments of briquetage (the remains of supports and/or pans used in salt production). Whilst this material is not unknown in medieval contexts it is generally associated with earlier salt industries. This could well be the case here, as virtually all of fragments were recovered from one of the channels, away from the main focus of medieval activity. It is noted that the assemblage includes a number of flatter pieces that may represent fragments of salt pans.
See assessment report (S2) for further details. Final reports awaited.
P. Watkins (HES), 16 April 2023.