I found this rock on Long Islands north shore in an estuary at low tide. It was worked by someone probably a long time ago. I think that because as seen in the pictures on on side of the rock it has one working and the other side has three workings though you can barely make out the third one is almost totally worn down. The holes are interesting because they are exactly the same, made up of 2 slightly oval holes and if you look close theres a raised straight line separating them. There were many Indian tribes on Long Island and most were settled around water for gathering food, fish, deer etc. eally have no idea....