The SU is a layer of rubble of unknown function, possibly part of wall. It was excavated till the disappearance of rubble and emergence of a soil layer which is similar throughout the layer and to the west. During post-excavation study, this feature was reinterpreted as a possible wall foundation that delimits the western extent of Space 1A-7, but this assignment is largely conjectural based on its alignment and construction technique from rubble and small stones.