This slide has experienced little displacement, but lidar reveals an impressive graben that is forming as a large mass of Hampton Shale (really a slate or phyllite here) bulges outward from the riverbank as it is undercut by Big Reed Island Creek. I think this indicates that the basal sliding surface slopes less steeply than the land surface, meaning the slide mass is thick and deep, particularly at its upslope end. The basal sliding surface could therefore be a bedding plane/foliation plane failure whose low dip is an expression of where it sits within the fold structure,.