This is a cut between two sections of the east retaining wall (4037 and 4039) of te road. It is rectangular in shape and is located east of the glariate road surface/ road preparation near where it meets the basalt road (4010). The west edge is uncertain, as layer 4020 filled this area (with no sign of the cut on the west), and the other edges are bounded by the edges of the walls 4037 and 4039. the east edge is cut into SU 4031. it looks like the cut represents the robbing of part of the retaining wall for the road.