The fill is not related to tufo wall SU 1058. It is not yet clear whether 1058 acts as a retaining wall for a wall of the same nature and composition as SU 1162 or if the fill represents the construction cut for wall 1058 (it doesn't). The composition of the fill changes from rubble to bedrock at circa 5m but this change cannot be explained without further excavation. Further excavation has reveal ashlar blocks at the bottom of the fill abutting SU 1162. At this level travertine blocks could also be found rpojecting from SU 1169 - the easternmost edge of the cut 1175.