Palisades Sill

The Palisades Sill as seen from the Palisades Interstate Parkway. The Hudson River is the background.

The Palisades Sill is a Triassic, 200 Ma diabase intrusion. It extends through portions of New York and New Jersey. It is most noteworthy for The Palisades, the cliffs that rise steeply above the western bank of the Hudson River. The ideal location and accessibility of the sill, as well as its unique features, have generated much attention from nature enthusiasts, rock climbers, and geologists alike.