Probably retaining wall for road 4010 (N/S orientation). Ends where the road ends with cut/broken edge in N where layer 4020 began. Southern limit ends where road starts to turn just N of excavation limit. Could also be a type of curb structure for road 4010 or perhaps a later construction built directly abutting paving 4010. SImilar in construction to wall 4013 on the E side of the road.