Passage 7.25.10
καταβάντων δὲ ἐκ Βούρας ὡς ἐπὶ θάλασσαν ποταμός τε Βουραϊκὸς ὀνομαζόμενος καὶ Ἡρακλῆς οὐ μέγας ἐστὶν ἐν σπηλαίῳ· ἐπίκλησις μὲν καὶ τούτου Βουραϊκός, μαντείας δὲ ἐπὶ πίνακί τε καὶ ἀστραγάλοις ἔστι λαβεῖν . εὔχεται μὲν γὰρ πρὸ τοῦ ἀγάλματος ὁ τῷ θεῷ χρώμενος, ἐπὶ δὲ τῇ εὐχῇ λαβὼν ἀστραγάλους ---οἱ δὲ ἄφθονοι παρὰ τῷ Ἡρακλεῖ κεῖνται---τέσσαρας ἀφίησιν ἐπὶ τῆς τραπέζης· ἐπὶ δὲ παντὶ ἀστραγάλου σχήματι γεγραμμένα ἐν πίνακι ἐπίτηδες ἐξήγησιν ἔχει τοῦ σχήματος.
When one descends from Boura toward the sea, there is a river called the Bouraïkos, and close by it a small statue of Heracles located within a cave. This Heracles is also surnamed Buraïkos, and here one can receive oracular answers by means of a tablet and dice. The person consulting the god first prays before the statue, and after prayer takes up four dice—an abundant supply of these lies ready beside Heracles—and casts them upon a table. For each combination turning up on the dice, there is set forth upon a special tablet the interpretation of that particular form.