Editing Eleusinion (section)

===Circular building===
A circular building was constructed 17.2 metres south of the South Stoa in Section II. It is known from a circular cutting in the bedrock and part of a poros wall, preserved to a height of 0.52 metres. The bedrock around the structure was smoothed down to create a flat area. The cutting indicates that it had a diameter of 7.75-8.00 metres, but the blocks of the wall come from an Archaic or Classical structure which was also circular, but larger, with a diameter of about 19 metres. This earlier structure must have been located somewhere else.{{sfn|Miles|1998|p=81}}

The floor was packed clay and at the exact centre of the room, a 1.35 metre wide [[millstone]] was set in the floor.{{sfn|Miles|1998|p=81}} There are no internal supports for a roof, so it may have been a simple flat structure of timber.{{sfn|Miles|1998|p=82}}

Remains of at least five altars were found nearby, confirming that the building served a religious function.{{sfn|Miles|1998|p=81}} Margaret Miles suggests that it was used for ritual dining. This is supported by the discovery of large amounts of cooking ware in the area. A well on the east side of the building may have been connected with this function.{{sfn|Miles|1998|pp=81-83}} In particular, the circular building may have been linked with meals held in honour of Plouton, who is known to have had a shrine in the City Eleusinion.{{sfn|Miles|1998|p=83}} It may also have been connected with the Thesmophoria.{{sfn|Miles|1998|p=83}}

The structure was built in the 2nd century BC, as shown by pottery from the fill of the foundations. Fills from the northwestern and eastern sections show it was dismantled and rebuilt with the same plan but a new floor around AD 100, probably in connection with a new drainage system, which closed the eastern well. A final set of fills show that it was partially dismantled in the late 2nd or 3rd centuries AD.{{sfn|Miles|1998|pp=82-83}}