Passage 8.25.6
τὸ μὲν δὴ παραυτίκα τὴν Δήμητρα ἐπὶ τῷ συμβάντι ἔχειν ὀργίλως, χρόνῳ δὲ ὕστερον τοῦ τε θυμοῦ παύσασθαι καὶ τῷ Λάδωνι ἐθελῆσαί φασιν αὐτὴν λούσασθαι· ἐπὶ τούτῳ καὶ ἐπικλήσεις τῇ θεῷ γεγόνασι, τοῦ μηνίματος μὲν ἕνεκα Ἐρινύς, ὅτι τὸ θυμῷ χρῆσθαι καλοῦσιν ἐρινύειν οἱ Ἀρκάδες, Λουσία δὲ ἐπὶ τῷ λούσασθαι τῷ Λάδωνι. τὰ δὲ ἀγάλματά ἐστι τὰ ἐν τῷ ναῷ ξύλου, πρόσωπα δέ σφισι καὶ χεῖρες ἄκραι καὶ πόδες εἰσὶ Παρίου λίθου·
At first, indeed, Demeter became angry at what had happened, but later, they say, her anger abated, and she chose willingly to bathe herself in the Ladon river. For this reason, the goddess gained additional surnames: "Erinys," because among the Arcadians anger is called "erinuein," and "Lousia" due to her bathing in the Ladon. The images within the temple are made of wood, but their faces, and the ends of their hands and feet, are made of Parian marble.