Ninham Mountain (NY)

Manitou Stone and a disturbed Stone Mound? 

http://www.poughkeepsiejournal.com/story/sports/2015/10/06/trail-marker-hiking-outdoors-recreation-ninham-mountain/73493184/

http://noahsage.com/2013/06/05/new-england-stone-chamber-ninham-mountain/

There's a "mysterious" stone chamber or two on the mountain and probably more stone features, but almost all the images I can find that aren't from pagan and celtic related websites are from UFO people monitoring sightings or mountain bike enthusiasts riding trails along interesting stone walls as well as off trail images where mountain bikers are using stones as jumps...

Still photo from: https://youtu.be/hdg3VGy-NLI

http://www.vitalmtb.com/photos/member/Covenant-drop-at-Mt-Creek,4322/Local-fall-ride,67937/Epic-Eli,10528