This is the construction trench for wall 2306. It is more clearly visible north of the wall, where it is cut into the compact floor surface (SU not yet assigned). To the east, where there is a gap in the wall, the limits and the bottom of the cut are difficult to determine. This gap may have served as the threshold into room C8 from the atrium, and it is possible that, as for room C7 the two separate cuts were made for two separate walls to delimit the northern boundary of this room, one on either side of the threshold. The layer of red tufo in the threshold continued under SU 2349, suggesting that it belongs to an earlier phase and strengthening the case for two separate cuts. This, the single easternmost stone of wall 2306 may possibly belong to a distinct wall/SU.