Passage 9.26.5
ἀπὸ δὲ τοῦ ὄρους τούτου πέντε ἀπέχει καὶ δέκα σταδίους πόλεως ἐρείπια Ὀγχηστοῦ· φασὶ δὲ ἐνταῦθα οἰκῆσαι Ποσειδῶνος παῖδα Ὀγχηστόν. ἐπʼ ἐμοῦ δὲ ναός τε καὶ ἄγαλμα Ποσειδῶνος ἐλείπετο Ὀγχηστίου καὶ τὸ ἄλσος, ὃ δὴ καὶ Ὅμηρος ἐπῄνεσε.
Fifteen stades from this mountain are the ruins of the city Onchestos; it is said that Onchestos, the son of Poseidon, dwelt there. In my time there still remained both the temple and the image of Poseidon Onchestios, and also the sacred grove, which Homer himself praised.