This singular stone appears to have a flat top. It is partly covered by SU 6178 and appears to be at a slight angle, with the northeaster section sticking out of the soil layer SU 6178 and the northwestern corner continuing down below SU 6178. This suggests that the stone may not be fully in its original position. It may have fallen slightly into a void not visible below the current surface level. We believe based on the shape of the stone and its relationship to at least two other drainage features (SU 6119 and SU 6216) that this stone was once a drain cover.