Monument record TQ 77 NW 209 - Low-tide ridge assemblage with heated architecture debris, Higham Marshes

An archaeological assemblage recorded as HCW 02. The assemblage dates from the Late Iron Age to the Roman period, broadly the mid‑1st to 2nd centuries AD, and consists of artefacts concentrated on a natural or erosional ridge on the foreshore that is exposed only at very low tide.

The material represents a secondary, water‑transported deposit rather than objects left in their original place of use. Large quantities of pottery and ceramic building material (CBM) have been washed upslope by river action from further out in the channel. The assemblage includes fragments of an aryballos (a small globular vessel used for oils or perfumes) and pieces of amphora, the large ceramic containers commonly used in the Roman world for transporting foodstuffs such as oil or wine. Together, these finds indicate activity connected with trade, transport, and possibly personal or domestic use rather than casual loss alone.

The character of the material strongly suggests the former presence of a heated Roman building, now largely lost to river erosion. This is demonstrated by exceptional quantities of hypocaust debris, including hypocaust flue tiles (ceramic box or channel tiles used to circulate hot air) and tegulae (flat Roman roof tiles). A hypocaust spacer, an element used to support raised floors in underfloor heating systems, provides particularly clear evidence for heated architecture. This structure is interpreted as part of a riverside facility, possibly a bath house, associated with a nearby river crossing or anchorage system. However, the deposit is not thought to be part of the same amenity complex as the nearby site known as OB 03, indicating multiple phases or structures along this stretch of river.

Artefacts are visible only at very low tides, when the ridge acts as a trap for material moved by the river. A significant proportion of the assemblage appears to originate from a gravel bank approximately 30 metres offshore, which is accessible only during exceptionally low tidal conditions. Ongoing tidal and storm activity continues to both replenish and remove material from the ridge, meaning that the assemblage is dynamic rather than stable.

The pottery includes BB2 (Black‑Burnished Ware 2), a characteristic Romano‑British coarse ware commonly produced in south‑east Britain; NKSH (North Kent Shell‑tempered ware); VRW (Verulamium Region Ware), associated with production around the Roman town of Verulamium (modern St Albans); and samian ware, the fine red‑gloss tableware also known as terra sigillata. The presence of a Dressel 20 amphora, a distinctive Spanish container type used primarily for olive oil, reinforces the Roman date and indicates participation in long‑distance trade networks. Other finds include a pierced antler tine, a bone hairpin, and the remains of horse skulls, suggesting a mix of domestic, craft, and possibly ritual or disposal activities.
Dating of the site relies on ceramic typology, the recognised forms of the amphora, and the characteristics of the glass present, all of which are consistent with activity in the 1st and 2nd centuries AD. The assemblage is closely associated with HCW 01, a nearby causeway, strengthening the interpretation of this area as a managed riverside zone linked to movement, transport, and infrastructure.

In terms of condition, the deposit is of low integrity because it is entirely secondary and subject to continuous natural reworking. It is also threatened by casual collecting as well as ongoing tidal and storm erosion. The recommended response is systematic, datum‑referenced collection across multiple tidal cycles, allowing the material to be quantified and analysed, particularly to understand supply patterns and building materials. Repeat collections after major storm events and during significant low tides are advised in order to track change and mitigate further loss of archaeological information. (1)

<1> Steve Trim, 2026, SHORNE/HIGHAM THAMESIDE ROMANO-BRITISH SITES 2012-2015+, HCW 02 (Unpublished document). SKE58794.