 These are sedimentary deposits of fluvio-marine origin from the Flandrian transgression which were covered by further formations, specifically peat, due to congestion and stagnation of watercourses.There are many peat bogs east of the communal territory extending into the neighbouring commune of Forges.The town has very little relief with the average altitude being 25 metres – ranging from the lowest point of 12 metres at "Lake Frace", to the highest point of 38 metres at the small hill, between the site of "Pannonière" and the low hills in the commune of "Saint-Christophe", north of "Aigrefeuille d'Aunis".