The SU is a pedestal for drainage feature 2513 and 2514. It is a layer of accumulation, probably part of leveling layer for the floor surface 2253. The eastern extent is at a lower elevation and is the layer below the drainage feature, rather than a true pedestal. During post-excavation study, this feature was reinterpreted as possibly one of the earliest deposits that might represent leveling fills for the 1A building, although the line differentiating leveling fills and natural accumulation is difficult to determine.