The SU is a layer of accumulation probably related to either abandonment activity of leveling activity in the Area C courtyard. During post-excavation study, this feature was reinterpreted as a potentially early leveling fill regularizing the topography of the central area of Space 1A-7 and leading into Space 1A-1.
The SU is an accumulation layer.
Friable grey-brown deposit S of cut 2493 in center of courtyard