SU 1389 is a layer of brown soil between the building in Area B to the west and the quarry debris to the east. It remains unexcavated, but is equal to SU 1413 just to the south, which was excavated. SU 1413 was a silty, naturally deposited layer that accumulated after the abandonment of the area. It was then cut into by quarry activities (cut 1409); the same situation probably holds for SU 1389.