Passage 2.11.2
καταβαίνουσι δὲ ὡς ἐπὶ τὸ πεδίον, ἱερόν ἐστιν ἐνταῦθα Δήμητρος· ἱδρῦσαι δέ φασιν αὐτὸ Πλημναῖον ἀποδιδόντα χάριν τῇ θεῷ τοῦ παιδὸς τῆς τροφῆς. τοῦ δὲ ἱεροῦ τῆς Ἥρας, ἣν ἱδρύσατο Ἄδραστος, ὀλίγον ἀπωτέρω Καρνείου ναός ἐστιν Ἀπόλλωνος· κίονες δὲ ἑστήκασιν ἐν αὐτῷ μόνοι, τοίχους δὲ οὐκέτι οὐδὲ ὄροφον οὔτε ἐνταῦθα εὑρήσεις οὔτε ἐν τῷ τῆς Προδρομίας Ἥρας. τοῦτον γὰρ δὴ Φάλκης ἱδρύσατο ὁ Τημένου, τῆς ὁδοῦ οἱ τῆς ἐς Σικυῶνα Ἥραν φάμενος ὁδηγὸν γενέσθαι.
As you descend towards the plain, there is here a sanctuary of Demeter. They say that Plemnaios set it up, giving thanks to the goddess for nurturing his child. A little further from the sanctuary of Hera, which Adrastus founded, is the temple of Apollo Karneios. Only columns remain standing inside it; you will find neither walls nor roof, nor indeed will you find them in the temple of Hera Prodromia. For this temple was established by Phalces, the son of Temenus, who said that the goddess guided him along the route to Sicyon.