Section of exterior wall of circular structure N of tufo paving 4055. After a cut of unknown function, continues N as well 4050. Cut on S by unknown action. Abuts interior wall 4053 on E--exterior wall may be later phase of circular structure or may be reinforcing wall. Circular structure not known. Abutted on NW by ashy layer 4045.
Southern semicircular walls 4052 outside 4053 inside