Passage 2.36.7
ἀναστρέψας δὲ ἐς τὴν εὐθεῖαν τόν τε Ἐρασῖνον διαβήσῃ καὶ ἐπὶ τὸν Χείμαρρον ποταμὸν ἀφίξῃ. πλησίον δὲ αὐτοῦ περίβολός ἐστι λίθων, καὶ τὸν Πλούτωνα ἁρπάσαντα ὡς λέγεται Κόρην τὴν Δήμητρος καταβῆναι ταύτῃ φασὶν ἐς τὴν ὑπόγεων νομιζομένην ἀρχήν. ἡ δὲ Λέρνα ἐστίν, ὡς καὶ τὰ πρότερα ἔχει μοι τοῦ λόγου, πρὸς θαλάσσῃ, καὶ τελετὴν Λερναίᾳ ἄγουσιν ἐνταῦθα Δήμητρι.
Turning back to the main road, you cross the Erasinus, and arrive at the river Cheimarron. Near it is an enclosure of stones, and here, they say, Pluto descended to the underworld, when he carried off Kore, the daughter of Demeter; this place is considered the entrance to the subterranean realm. Lerna, as my previous account stated, lies near the sea, and here they perform the festival Lernaia in honor of Demeter.