Grooved boulder main content.

Grooved boulder

Part of Hall of Planet Earth.

Close-up of grooved boulder in Hall of Planet Earth AMNH/D. Finnin

Poke-O-Moonshine Mountain, Adirondacks, New York

Rocks and pebbles embedded in the underside of flowing glaciers created the grooves, called glacial striations, on the surface of this granite gneiss. Glacial striations show the direction the ice flowed.

AMNH Collections