NHER 66864 (Monument record) - Undated possible salt-filtration unit and former watercourses and drains

September 2016. Geophysical Survey.
Magnetometer survey of part of large proposed development site.
Several areas of magnetic disturbance recorded at the western and eastern margins of this field correspond with sinuous former drainage channels or watercourses shown on the South Wootton tithe map (S1). Magnetic disturbance in the extreme south-west corner of the field corresponds with another former boundary depicted on 19th-century maps, the line of which is still followed by the King’s Lynn/South Wootton parish boundary. Other areas of magnetic disturbance in the south-western part of the site are though of uncertain nature. These responses are of interest as this part of the site coincides with a record relating to a medieval saltern that had possible been converted into a post-medieval fort (NHER 13784). Analysis of the available aerial imagery does though suggest that the principal remains lay to the south of this field There was no evidence for surviving remains associated with a second probable saltern mound visible as an earthwork on aerial photographs at the southern end of the site (NHER 27129).
This field has a very different magnetic signature to that of the land to the east, with numerous small dipolar anomalies present. As with the field to the north (NHER 66861) it is suggested this might be the result of material having been imported to improve the soil. It is possible that this magnetic noise has masked any smaller archaeologically-significant anomalies present.
See report (S2) for further details.
P. Watkins (HES), 18 April 2023.

April 2017. Desk-based Assessment.
See report (S3) for further details.
P. Watkins (HES), 18 April 2023.

May 2017. Earthwork Survey.
Although primarily focused on a group of probable ridge and furrow earthworks in the field to the east (NHER 62316) part of the southern end of this site was also examined due to the possible presence of a saltern mound (NHER 27129). Although visible as an earthwork on aerial photographs it appears that this mound no longer survives.
See report (S4) for further details.
P. Watkins (HES), 18 April 2023.

February-May 2018. Trial Trenching.
Evaluation of part of large proposed development site (Field 6; Trenches 17-40).
The 24 trenches excavated at this location revealed a small number of scattered features, the most interesting of which lay in the south-west part of the site. Here a trench exposed the edge of a large feature with a primary fill consisting of lenses of redeposited natural sand and darker, potentially charcoal-rich material, overlain by what appeared to be redeposited alluvial silt. This feature lay in the immediate vicinity of a probable saltern mound (NHER 13784) and potentially represented part of a filtration unit in which salt-impregnated silts were processed to create a brine solution that could then be boiled down to extract salt. A sample from its primary fill was found to contain a concentration of small-diameter twigs (including heather), which may represent the remains of an organic filter used as part of this process. Numerous fragments of fired clay were also present, along with a lead object of uncertain nature. No trace of the saltern mound itself was recorded, although, as noted above, aerial photographs suggest that the main earthwork lay to the south of this site.
Although three of the excavated trenches were placed to coincide with the possible saltern mound that does fall within the southern half of this site (NHER 27129) no associated features or deposits were revealed.
The only other remains recorded were two linear features close to the eastern edge of the site. These included a broad, east-to-west aligned feature though to represent a natural channel. This produced two sherds of medieval pottery. A north-east to south-west aligned feature to the south corresponded with one of the sinuous drains shown on the South Wootton tithe map (S1).
It appears that a semi-waterlogged peat deposit was also uncovered in one of the southernmost trenches, although its context is not described. A sample from this deposit contained no indicators of associated anthropogenic activity.
Unstratified finds were limited to a small assemblage of Late Saxon and medieval pottery sherds.
See report (S4) for further details.
P. Watkins (HES), 18 April 2023.