Passage 10.12.1
πέτρα δέ ἐστιν ἀνίσχουσα ὑπὲρ τῆς γῆς· ἐπὶ ταύτῃ Δελφοὶ στᾶσάν φασιν ᾆσαι τοὺς χρησμοὺς γυναῖκα ὄνομα Ἡροφίλην, Σίβυλλαν δὲ ἐπίκλησιν. τὴν δὲ πρότερον γενομένην, ταύτην ταῖς μάλιστα ὁμοίως οὖσαν ἀρχαίαν εὕρισκον, ἣν θυγατέρα Ἕλληνες Διὸς καὶ Λαμίας τῆς Ποσειδῶνός φασιν εἶναι, καὶ χρησμούς τε αὐτὴν γυναικῶν πρώτην ᾆσαι καὶ ὑπὸ τῶν Λιβύων Σίβυλλαν λέγουσιν ὀνομασθῆναι.
There is a rock projecting above the ground; the Delphians say that on this rock a woman named Herophile, surnamed the Sibyl, stood to chant her oracles. Examining earlier traditions, I found that this woman was particularly similar to an earlier one whom the Greeks declare to have been the daughter of Zeus and Lamia, herself child of Poseidon, and they say that she was the first woman to chant prophecies and was named Sibyl by the Libyans.