What is "helisson"

Helisson was an ancient town in Arcadia, Greece. It was situated near the source of the river Helisson (present Elissonas), a tributary of the Alfeios. There was a temple of Poseidon with a statue of the god. Pausanias (2nd century AD) found the head of the statue still remaining. The town was founded by Helisson, a son of Lycaon. The town was abandoned, along with most other cities in Arcadia, when Megalopolis was founded. The location of the town is unknown; Leake placed it near present Alonistaina and Ross placed it near Piana, both located on the eastern slope of the Mainalo mountains.