Passage 6.19.2
τοῦτον ᾠκοδόμησεν ὁ Μύρων νικήσας ἅρματι τὴν τρίτην καὶ τριακοστὴν Ὀλυμπιάδα. ἐν δὲ τῷ θησαυρῷ καὶ θαλάμους δύο ἐποίησε, τὸν μὲν Δώριον, τὸν δὲ ἐργασίας τῆς Ἰώνων. χαλκοῦ μὲν δὴ αὐτοὺς ἑώρων εἰργασμένους· εἰ δὲ καὶ Ταρτήσσιος χαλκὸς λόγῳ τῷ Ἠλείων ἐστίν, οὐκ οἶδα.
This was built by Myron, who had won the chariot-race at the thirty-third Olympiad. In this treasury he constructed two chambers, one in the Dorian style, the other in Ionian workmanship. I saw myself that they were made of bronze; however, whether this bronze was the so-called Tartessian bronze, as claimed by the Eleans, I cannot say.