This appears to be a late ancient fill of a cut. While the surrounding areas were excavated or back-filled by the previous excavations by the soprintendenza, no modern materials were found in the fill. The area was undisturbed because it was covered by SU 5569, indicating that the fill is indeed ancient. In the area where the fill met pier 5470, excavation revealed ancient concrete with tile inclusions which passed under wall 5469 indicating that the walls are in secondary deposition. This suggests in conjunction with the interpretation of su 5588 that the ashlar walls previously interpreted as the original southern limit of the complex must instead belong to a later phase.