The Black Dyke is an earthwork feature defined by a ditch up to 1.8m deep on its west side. The purpose of the dyke is not known but it is thought to date to before the Roman period. It runs for several kilometres from the west of Bellingham south and westwards through Wark Forest. Some sections are visible on aerial photographs and it is suggested that the dyke may have been an intermittent feature rather than a continuous one. In some places, later parish boundary walls follow the line of the dyke.