The earthwork remains of an oval mound, possibly a medieval saltern mound, located adjacent to Hamshill Creek in Grain Marshes. The mound measured approximately 15m x 30m. The mound was seen as an earthwork and was mapped from Environment Agency lidar imagery as part of the English Heritage: Hoo Peninsula Landscape The earthworks of a post medieval sea wall can be seen on aerial photographs taken in 1947. This earthwork was situated on the northern side of Damhead Creek and could be traced for 350m. This earthwork has since been levelled. This site was mapped from aerial photographs as part of the English Heritage: Hoo Peninsula Landscape Project.