NHER 28348 (Monument record) - Medieval to post-medieval sea defence

Linear earthwork. Running North-South. Informant suggests it once continued as far north as Scaleshowe Bank (21808).
From its position north of the North Sea bank (NHER 21807) which he considers to be mid 11th century and south of Scaleshowe Bank, which he believes to be 13th century, informant suggests this bank should be 12th century, but has not found any documentary references and notes that R. Silvester does not agree with the dating. Part of the bank now used in wall of reservoir, remainder to be preserved on industrial estate, but cut made for new road. This showed that bank is composed entirely of soil, disturbed in recent years for insertion of electricity cable. Only find was one tibia (left hand) of horse more than four years old at time of death; butchered. Date not ascertainable
Identified by T. Ashwin, (NAU).
Information on excavation from L. Brewster, (KLM).
E. Rose (NAU), 4 September 1991 & 24 January 1992.

July 2003. NMP.
Earthwork of probable medieval to post-medieval date visible on 1947 RAF aerial photographs (S1). The earthwork is visible in a fragmentary form as three stretches of bank running from TF 60965 16971 to TF 60966 17723. The line of the bank is depicted on the 2nd edition map (1902-7, 25") (S2). This shows the line of the earthwork in one continuous bank from TF 60965 16971 to TF 60836 17867. This bank appears to be cut by the River Great Ouse Eau Brink Cut to the north. On the opposing north side of the Cut there is another section of sea bank, continuing round to the west (NHER 21808). It is possible that these banks were originally part of the same scheme. This bank has been suggested as being thirteenth century in date. It is therefore possible that this southern stretch of bank is also medieval in date, although the relationship is not certain and the bank may be post-medieval in date.
M. Brennand (NMP), 6 August 2003.

March 2010. Borehole Survey.
A window sampling exercise was undertaken in response to a proposed development at King’s Lynn Power Station. The principal objective of this work was to determine whether the medieval/post-medieval sea bank survives within the present bank and if establish its likely date. A total of 10 window samples were taken of which two were selected for detailed recording (the same deposit sequence being duplicated in all of the cores scanned).
The sea-bank was clearly visible in the cores, represented by firm, massive clays which overlaid what were probable intertidal Flandrian silts with intercalated peats. No finds were recovered although small fragments of charcoal were present throughout the bank deposits and may provide suitable material for radiocarbon dating. Diatom and pollen samples were also taken to determine the likely source of the bank material and to confirm the nature of the underlying deposits.
Cross sections constructed from the available data suggest that the bank and the upper deposits of the adjacent land are composed of similar alluvial material but at quite different depths. This suggest that these alluvial sediments were deposited by the river Great Ouse following the construction of the banks.
See report (S3) for further details.
Material associated with this work has been deposited with Norwich Castle Museum (NWHCM : 2025.244).
Amended by P. Watkins (HES), 18 April 2018 and 12 October 2025.

November 2010. Excavation.
Excavation undertaken as mitigation ahead of the proposed expansion of the power station. Three wide, stepped trenches were dug through the sea bank using a combination of machine and hand excavation. The bank was shown to survive to a height of between 3.8 and 3.92m OD. There was clear evidence for two episodes of bank construction, with the deposits associated with the first phase overlain by layers of windblown sand. In two of the three trenches there was also evidence for a third phase of bank construction. Most of the bank layers consisted of separate deposits of silty sand, although some clay was also present.
The only find recovered was a single fired clay fragment that was found in one of the deposits associated with the earliest bank. This was possible a piece of briquetage from a local salt making site but is not closely datable and in any case was most probably residual within the material used to construct the bank. A number of environmental samples were processed and although these produced some charred macrofossils (including cereal fragments) the assemblages were extremely small, making it impossible to confidently distinguish remains that may be contemporary with the deposits and those that may be intrusive. No diatoms were identified in any of the sediments analysed.
The only other feature noted during this work was a ditch of recent date in the northernmost trench. No unstratified finds were recovered.
The natural deposits beneath the mound were shown to be predominantly slightly laminated firm clays that had probably formed in a freshwater marsh.
See assessment report (S4) for further details. Final report awaited.
The archive associated with this work has been deposited with the Norwich Castle Museum (NWHCM : 2011.149).
P. Watkins (HES), 18 April 2018 and 12 May 2019.