This irregular concrete plug of large travertine and tufo blocks seems to function as a later plug on the probable doorway between rooms H-10 and H-12 where the tufo block 7358 is located. The construction of this tufo plug was likely associated with the reorganization/renovation of the trapezoidal structure to close off access between spaces. The smooth facing of the eastern side seems to show that the builders were more concerned with the plug's appearance in room H-10 and not in H-12.