The plains of the Marais Vernier extend over 12,355 acres (5,000 ha) on the Roumois plateau, between Quillebeuf and the tip of La Roque. It is an old abandoned meander of the Seine where significant biodiversity has developed. Strips perpendicular to the slope alternate with orchards, holly hedges, and wet meadows interspersed with tadpole willows (topped tree in the shape of a large head).