Further study indicated that this large layer was associated with the collapse and abandonment of the Republican house.

Excavated in 2011. Appears to be packed against SU541.

Concentration of large chunks of basalt, two visible chunks of travertine, numerous fragments of tufo (mostly gray but also some brown-orange with white inclusions) and some visible sherds of tile and pottery (including a base and large handle at the south end). Looks like a collapse, but the large chunks of basalt also look like they may be aligned linearly along the west side (running southwest-northeast) and the north side (running west-east) and may thus represent the construction of a wall. The layer was left unexcavated at the end of the 2010 season.