Passage 8.10.4
θαλάσσης δὲ ἀναφαίνεσθαι κῦμα ἐν τῷ ἱερῷ λόγος ἐστὶν ἀρχαῖος· ἐοικότα δὲ καὶ Ἀθηναῖοι λέγουσιν ἐς τὸ κῦμα τὸ ἐν ἀκροπόλει καὶ Καρῶν οἱ Μύλασα ἔχοντες ἐς τοῦ θεοῦ τὸ ἱερόν, ὃν φωνῇ τῇ ἐπιχωρίᾳ καλοῦσιν Ὀσογῶα. Ἀθηναίοις μὲν δὴ σταδίους μάλιστα εἴκοσιν ἀφέστηκε τῆς πόλεως ἡ πρὸς Φαληρῷ θάλασσα, ὡσαύτως δὲ καὶ Μυλασεῦσιν ἐπίνειον σταδίους ὀγδοήκοντα ἀπέχον ἐστὶν ἀπὸ τῆς πόλεως· Μαντινεῦσι δὲ ἐκ μακροτάτων τε ἡ θάλασσα ἄνεισι καὶ ἐκφανέστατα δὴ κατὰ τοῦ θεοῦ γνώμην.
There is an ancient tradition that says a wave from the sea appeared in the sanctuary. Similar stories are told by the Athenians concerning the wave on their Acropolis, and by the Carians from Mylasa about the sanctuary of the god whom they call, in their local tongue, Osogoa. Now, the Athenians are situated about twenty stades from the sea at Phalerum, and likewise the port serving the people of Mylasa is eighty stades distant from their city. But for the Mantineans, the sea is the farthest removed and thus its appearance here is most clearly a manifestation of divine intent.