Native American Indians believed Seneca Lake to be a bottomless lake, with a monster that lived in its depths. Almost forty miles long each and one to three miles in width, the pitch-black depths of both of them, hundreds of feet deeper than sunlight can penetrate, descend to depths below sea level.
https://www.ithaca.com/news/here-there-be-monsters-diving-into-the-legacy-of-the-beasts-of-the-finger-lakes/article_6ea32908-90e7-11e8-879f-63ae3308b591.html
Here there be monsters: Diving into the legacy of the beasts of the Finger Lakes
By Charley Githler Jul 26, 2018 Updated Aug 1, 2018