Passage 8.30.1
ὁ δὲ Ἑλισσὼν οὗτος ἀρχόμενος ἐκ κώμης ὁμωνύμου ---καὶ γὰρ τῇ κώμῃ τὸ ὄνομα Ἑλισσών ἐστι---τήν τε Διπαιέων καὶ τὴν Λυκαιᾶτιν χώραν, τρίτα δὲ αὐτὴν διεξελθὼν Μεγάλην πόλιν, εἴκοσι σταδίοις ἀπωτέρω Μεγαλοπολιτῶν τοῦ ἄστεως κάτεισιν ἐς τὸν Ἀλφειόν. πλησίον δὲ ἤδη τῆς πόλεως Ποσειδῶνός ἐστιν Ἐπόπτου ναός· ἐλείπετο δὲ τοῦ ἀγάλματος ἡ κεφαλή.
This Elisson river rises from a village of the same name—for indeed the village is also called Elisson—and flows through the territories of the Dipaeans and the Lycaeatae, and thirdly passing through the city of Megale, it joins the Alpheios twenty stadia from the city of the Megalopolitans. Near the city is a temple dedicated to Poseidon Epoptês; the head of his statue was missing.