Clusters of pits are visible as earthworkS on lidar imagery and on some historical air photos. These pits, more than 30 and approximately 5m in diameter are likely to be the remains of post medieval coal workings. These remains are located at Plessey Flats, and in a neighboouring field. Those in the flats are obscured by trees, those in the field have a shallower and more rounded appearance. Within the flats the pits appear to cut medieval ridge and furrow.