Passage 10.6.1
πόλιν δὲ ἀρχαιοτάτην οἰκισθῆναί φασιν ἐνταῦθα ὑπὸ Παρνασσοῦ, Κλεοδώρας δὲ εἶναι νύμφης παῖδα αὐτόν· καί οἱ πατέρας, καθάπερ γε καὶ ἄλλοις τῶν καλουμένων ἡρώων, Ποσειδῶνά τε θεὸν καὶ Κλεόπομπον ἄνδρα ἐπονομάζουσιν. ἀπὸ τούτου δὲ τοῦ Παρνασσοῦ τῷ τε ὄρει τὸ ὄνομα τεθῆναι λέγουσι καὶ ἀπὸ τούτου Παρνασσίαν ὀνομασθῆναι νάπην· τῶν πετομένων τε ὀρνίθων τὴν ἀπʼ αὐτῶν μαντείαν γενέσθαι Παρνασσοῦ τὸ εὕρημα.
They say that in this place the most ancient city was founded by Parnassus, who was himself the son of the nymph Cleodora. As with others who are called heroes, they name two fathers for him: the god Poseidon and a mortal man, Cleopompus. It is said that from this Parnassus the mountain derived its name, and that the ravine itself is also called Parnassian after him. Moreover, divination by observing the flight of birds is said to have been discovered by Parnassus.