As no ship wreck was found in the vicinity, the reason of the presence of these amphora fragments, whose faces present a large accumulation of oyster shells, is unknown. Reconstructed geomorphological maps of the area present Mermian as a riverine site already at this period, and several hypothetical explanations on the role of these amphorae exist landfill linked to a neighbouring habitat, bank reinforcement linked to a ford crossing, river landing, etc.
In order to define whether the amphorae were transported to this location and from where, we analysed the stable carbon and oxygen isotopes of the oyster shells. Moreover, the analysis of Mytilaster sp.
Transport to Mermian from a coastal locality is unlikely but may still have happened, although no trace of human handling were observed on the fragments. Still, the presence of other marine or brackish molluscs in the sediment discards the interpretation of Mermian being a continental locality. This singular discovery, added to several testimonies of looting in its immediate surroundings, subsequently motivated the realization of several archaeological surveys between and , followed in and by two campaigns consisting in the realization of test pits Rivalan et al.
At the end of the latter, it appeared that, despite the presence of actual traces of looting on the site, the initial hypothesis of an ancient boat wreck had to be rejected. The many test pits carried out indicate the existence of an important dump 18 m 2 , 30β40 cm thick of fragmented italic amphorae dating from the end of the 2 nd century BC or the beginning of the 1 st century BC, whose faces present a large accumulation of oyster shells.
Despite these facts, the reasons for such an accumulation of ceramics in this part of the river remain highly uncertain i. If this geographical context leads to the existence of areas systematically located in dry locations and provided with a good building material i. The reconstructed extension borders of the lagoons from the 2 nd century BC are indicated in green from Devillers et al.
