It is located northeast of Polydross and right on the edge of the residential area. It was discovered by chance in 1928 by the discovery of a tombstone inscribed with the inscription ΜΝΑΣΙΚΛΕ(ΙΑ) ΔΑΜΑΤΡΙ ΚΑΙ ΚΟΡΗ. A systematic excavation was carried out by X. Carouzos during the years 1928-1932 which revealed in 1/3 of it, a sanctuary of the goddess Demeter and her daughter Persephone with numerous votive offerings. All were transferred to the Arch. Museum of Thebes. From a silver cup of the excavation with the inscription ΔΑΜΑΤΡΙ ΕΝ ΕΡΩΧΟΙ, the location of the ancient Erochos south of Polydros was also identified, which until then was mentioned in the sources (Herodotus, Pausanias) but remained unidentified.