Monument record TQ 77 NW 1366 - ?Medieval saltern mounds, Cliffe

The earthwork remains of a several irregular conjoined mounds centred at TQ 7235 7821 which may be be one of a number of medieval saltern mounds identified in the area. The site appears as a curvilinear raised area measuring 50m x 60m with a further raised lobe on its southern side 25m x 45m. There appeared to be a depression in the centre of the main mound.

Saltern mounds are the result of large-scale salt manufacturing where brine was extracted from salt-rich sands and sediments, concentrated and evaporated using process known as sleeching. The discarded waste material from the process built up around the production area into a sizeable mound, often with a hollow in the centred where a hut stood. These medieval saltern mounds are typically described as `floriate' in form because of their irregular lobed formation of dumped waste. They often occur in clusters around former and surviving tidal water-courses within the marsh. There has been considerable reclamation and subsequent sea wall construction since the medieval period which has isolated these sites from the sea.

Many of these mounds were subsequently utilised as sheepfolds, sheep washes and stock refuges in the post medieval period because of their slightly elevated position in the readily flooded marshes.

Roman finds have been extracted from some of these sites, but are believed to be from the lower levels, and not associated with the mounds. Post-Roman flooding and silt deposition has resulted in Roman sites lying typically several feet below the current land surface.

This site was mapped from 1953 RAF aerial photographs as part of the English Heritage: Hoo Peninsula Landscape Project. (1)

A group of irregular earthworks roughly enclose an area of 90m x 40m and comprise a low level, sub-rectangular space bracketed by a bank at the north end and a pair of angular hollows to the south. This complex may be the remains of a saltern or, less likely, a sheepfold. The feature is located within an area of Cliffe Marshes that became an extensive chemical explosives factory established by Curtis’s & Harvey Ltd in 1900, operational until 1921-2 and now largely dismantled (TQ 77 NW 121 uid 1075508 / TQ 77 NW 154 uid 1517194). The remnant structures and earthworks of the explosives works were subject to a detailed survey and investigation by English Heritage in 2011-13; as a result the saltern was surveyed at 1:1000 as an earlier feature recorded amongst the wider factory remains. (2)

<1> RAF, 1953, NMR RAF/82/713/ 0353 06-FEB-1953 (Photograph). SKE58845.

<2> English Heritage, 2013, Curtis's and Harvey Ltd Explosives Factory, Cliffe and Cliffe Woods, Medway. Archaeological Survey and Analysis of the Factory Remains Volume 2 of 2. (Bibliographic reference). SKE31442.