The wall appears to be a filler between the two tufo blocks between which it is built. The blocks were placed earlier than the wall, but it is unclear if there had been a space left or if a block had been robbed out. There is a similar structure to the west on the other side of space 10. As there is no longer an existing wall running east-west (with the exception of the tufo coursework which constitutes a threshold farther to the east), it is possible that another petit appareil wall connected to and extended from this existing fragment. Although it is not unlikely that it extended east at the same thickness and the fragment is so thick only as a means of completely filling the space between the two tufo blocks. Another possibility is that the wall continued to extend to the north perhaps creating the eastern limit of space 10 in a late phase.