Kent Archaeological Review extract

A Preliminary Note on Briquetage from the Upchurch Marshes.
by Ian Jackson.

The type of sites under the Upchurch Archaeological Group's observation in the large alluvial tract which forms a large part of the southern expanse of salt marsh and mudflat in the Medway estuary, indicate that the economy of the area during the 1st and 2nd centuries AD had been based on various activities, one of which was salt winning. Out of the 22 sites under observation 8 belong in this category. See Footnote [1]

Four of these salt sites appear to be related to farming in which stock raising seems to have played an important role. Such a salt site could have formed an integral part of a farm's subsistence, worked not only to meet their own requirements but also to supplement any deficiencies in other farm activities.

The most common factor met on all salt sites are the variations that occur in the furniture used at the firing stage of the process, this, no doubt, represents the individual approach to the process influenced perhaps by site conditions or local tradition.

It is such a varient from 4 sites that is the subject of this discussion.

The Fragments (Slotted Material).

The fragments as found are in a fragile condition often crushed, their shape being retained by a soft surrounding deposit. Fragments of a more stable material of varying size and shape have been retrieved, and of these the fragment illustrated in Figure 1 is the best specimen yet found.

An individual fragment may measure up to 300 milemetres in length and is of roughly rectangular section, three faces of which have been subjected to a firing. The fragment shows varying degrees of burning throughout while the three faces are oxidised and are red-yellow in colour. It would seem that the fragment represents part of a ridge, constructed with wet clay containing a grog of crushed briquetage that was formed on the ground and varied in height from 70-100 millimetres. See Footnote [2]

Along one face, or occasionally both, as in Figure 1, slots occur at approximately 70 millimetre centres. The slot width varies from 6-10 millimetres and are impressions of thin briquetage fragments broken roughly to shape to form supports and pushed into the soft clay ridge. Remains of these supports have been found in situ. (Figure 1). Slots on the opposite face when they occur, as in Figure 1, measure 20 millimetres in width and and are well formed impressions. The impressions match the widths of bar and wedge fragments from the same deposits which seems to indicate that they formed an integral part of the same structure to which the slotted material belongs. Although it is fairly certain that the fragment represents part of the main support of a structure, which edge to regard as the base is debatable and the reader is requested to examine both view 2.1 and 2.2 of Figure 1, as one of these two edges formed the base.

The Find Conditions.

Close examination of the mudflats adjacent to the eroding marsh face at low tide will reveal various accumulations of the slotted material. As the material is. found under various conditions it will be convenient to consider them at each site.

Site 004.

Slotted material found in two rectangular formations being approximately 600 millimetres in width and varying in length from 900 millimetres to 1500 millimetres. The deposits are quite dense and are mixed with and appear to be sitting on a reddish brown- black ash deposit.

The formations are located close to a ditch feature on the site and some examples of the slotted material had found their way into the ditch's domestic fill.

Site 005.

Large deposits of the material have been found in a ditch feature on the site. As far as we can ascertain, the ditch measures 1000 millimetres in width and when sectioned showed intermittent tip lines.

Two separate deposits of slotted material were noted, both tipped from the same side of the ditch.

Site 012.

Material found in three rectangular formations of similar dimensions to site 004. The large deposits of briquetage waste surrounding the site would indicate an extensive use of this area for salt winning.

Site 015.

The gradual erosion of a briquetage deposit, has revealed, concentrations of the slotted material. The edges of these concentrations at times appear to have Figure 1 . Fragment of briquetage associated with the process of salt-winning from sea water. straight edges. On one occasion an irregular but roughly circular edge appeared to enclose a deposit of reddish brown-black ash. These concentrations of material within the general briquetage waste may represent the periodic firing and consequent destruction levels of structures.

DRAWING: Fragment of briquetage.

Figure 1.
Fragment of briquetage associated with the process of salt-winning from sea water.


The large amounts of brine evaporating vessel fragments, of a type common to many salt sites, found with the slotted material would indicate that the fabric originates from the evaporation sequence of salt winning. The absence of fire pits or hearths on the sites suggest that the material is probably the remains of a collapsed free standing structure. See Footnote [3]

What actual form the construction took will be difficult to ascertain. The slotted material may have been used as either a base for briquetage supports steadying the evaporating vessels adjacent to a fire, or by using two parallel ridges of the slotted material, supporting the vessels if spanning the fire.

A more developed form of construction may be suggested by the fragments of bar and wedge pieces found with the material. This form could have taken the shape of a low wall that provided the main support for a superstructure of a bar and wedge construction.

Although the group has attempted reconstructions it became obvious after discussions with various delegates at the Colchester Salt Conference that attempting reconstructions at this present time may be premature. So many alternative suggestions were forthcoming that it became clear that the material must be examined and discussed again, together with recently found material before committing ourselves to a reconstruction.


I think we can be quite confident after examining pottery contemporary with the slotted material that the sites in question were active during the first quarter of the 1st century. Just how long these sites were active is difficult to say but evidence at present seems to suggest that there may have been a lull in salt production sometime during the latter half of the 1st century.

At this time the method of evaporation as represented by our material seems to disappear. No slotted material has been found in the late 1st and 2nd century deposits in the area although hearths3 with associated briquetage have occurred.


I must thank all delegates at the Salt Conference who found time to discuss the material and in particular Dr P L Gouletquer, who kindly provided suggestions for possible reconstructions that were both persuasive and greatly appreciated.

The group also thank Mr H Mouland and Mr M Webb for allowing them to continue visiting sites on their property.


Footnote 1.

Distribution map can be obtained from the groups representative. Return to the paragraph.

Footnote 2.

Collective term describing debris resulting from the process of salt-winning from sea-water. Return to the paragraph.

Footnote 3.

Hearth, term used here to describe firing area of a permanent nature. Return to the paragraph.
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