Monument record CHF 033 - Post Medieval relict sea bank or causeway, visible as an earthwork.

The earthwork remains of a possible causeway or flood bank are visible in the inter-tidal area of the Butley River on aerial photographs of 1943 onwards, centred on circa TM38855167 roughly 100m to the south-west of the duck decoy pond, Chillesford parish (S1). It is in total about 420m in length, but is unusually constructed, doubling back on itself and then partially arranged in a 'V' shaped, almost zigzag form towards its southern end. It is not marked as a bank on the first or second Ordnance Survey maps of circa 1884 or 1904, but there is marked on these maps a rectangular pit or pool that appears to tally with the area of saltmarsh enclosed by the bank as it doubles back on itself (S2, S3). The bank may therefore have been constructed to protect this pool or pit from flooding, or to provide access to it. However, this pit is has probably silted up and is not visible on the aerial photographs. (S4)