Passage 5.13.8
ἔστι δὲ ὁ τοῦ Διὸς τοῦ Ὀλυμπίου βωμὸς ἴσον μὲν μάλιστα τοῦ Πελοπίου τε καὶ τοῦ ἱεροῦ τῆς Ἥρας ἀπέχων, προκείμενος μέντοι καὶ πρὸ ἀμφοτέρων· κατασκευασθῆναι δὲ αὐτὸν οἱ μὲν ὑπὸ Ἡρακλέους τοῦ Ἰδαίου λέγουσιν, οἱ δὲ ὑπὸ ἡρώων τῶν ἐπιχωρίων γενεαῖς δύο ὕστερον τοῦ Ἡρακλέους. πεποίηται δὲ ἱερείων τῶν θυομένων τῷ Διὶ ἀπὸ τῆς τέφρας τῶν μηρῶν, καθάπερ γε καὶ ἐν Περγάμῳ· τέφρας γὰρ δή ἐστι καὶ τῇ Ἥρᾳ τῇ Σαμίᾳ βωμὸς οὐδέν τι ἐπιφανέστερος ἢ ἐν τῇ χώρᾳ τῇ Ἀττικῇ ἃς αὐτοσχεδίας Ἀθηναῖοι καλοῦσιν ἐσχάρας.
The altar of Olympian Zeus is situated at roughly equal distances from the Pelopion and the sanctuary of Hera, but lies somewhat in front of both. Some say it was built by Idaean Heracles, while others claim it was constructed two generations later by local heroes, subsequent to Heracles. This altar is formed from the ashes of the thighs of sacrificial victims offered to Zeus, just as is also the case at Pergamon; similarly, the altar dedicated to Hera of Samos is also composed of ashes, though it is no more outstanding than those found in Attica, which the Athenians call "improvised hearths."