The SU is a layer of natural accumulation bounded on the west and south by an ashlar tufo wall, on the east by the road and on the north by the 2010 excavation limit. The inclusions are fairly evenly distributed throughout layer with the exception of a cluster of un0worked tufo and basalt (cobble-sized) in the northeast and north-central parts of the area. The patch in the northeast may be the collapse of a retaining wall of the road. We stopped at same level as the area of the 2010 excavation to the north of the SU, where we came down on a more compact layer with some orange-red patches and more charcoal. During post-excavation study, this feature was reinterpreted as an accumulation layer marking the abandonment of the area.