Passage 1.32.7
ἔστι δὲ ἐν τῷ Μαραθῶνι λίμνη τὰ πολλὰ ἑλώδης· ἐς ταύτην ἀπειρίᾳ τῶν ὁδῶν φεύγοντες ἐσπίπτουσιν οἱ βάρβαροι, καί σφισι τὸν φόνον τὸν πολὺν ἐπὶ τούτῳ συμβῆναι λέγουσιν· ὑπὲρ δὲ τὴν λίμνην φάτναι εἰσὶ λίθου τῶν ἵππων τῶν Ἀρταφέρνους καὶ σημεῖα ἐν πέτραις σκηνῆς. ῥεῖ δὲ καὶ ποταμὸς ἐκ τῆς λίμνης, τὰ μὲν πρὸς αὐτῇ τῇ λίμνῃ βοσκήμασιν ὕδωρ ἐπιτήδειον παρεχόμενος, κατὰ δὲ τὴν ἐκβολὴν τὴν ἐς τὸ πέλαγος ἁλμυρὸς ἤδη γίνεται καὶ ἰχθύων τῶν θαλασσίων πλήρης. ὀλίγον δὲ ἀπωτέρω τοῦ πεδίου Πανός ἐστιν ὄρος καὶ σπήλαιον θέας ἄξιον· ἔσοδος μὲν ἐς αὐτὸ στενή, παρελθοῦσι δέ εἰσιν οἶκοι καὶ λουτρὰ καὶ καλούμενον Πανὸς αἰπόλιον, πέτραι τὰ πολλὰ αἰξὶν εἰκασμέναι.
In Marathon there is a lake that is marshy for the most part; into this lake the foreigners fell when fleeing, through ignorance of the roads, and it is said that this was largely responsible for the great slaughter among them. Beyond the lake are stone mangers of the horses of Artaphernes, and marks of his tent remain upon the rocks. A river flows out of the lake, near which it provides water suitable for cattle, but at its mouth flowing into the sea it becomes salty and is filled with sea fish. A little way further from the plain is the hill of Pan, where there is a cave worthy of seeing; the entrance to this cave is narrow, but once inside there are chambers and baths, and the place called the goat-shed of Pan—stones that mostly resemble goats.