Palisades, cliffs along the west bank of the Hudson River, NE N.J. and SE N.Y., extending from N of Jersey City, N.J., to the vicinity of Piermont, N.Y., with a general altitude of from 350 ft to 550 ft (107–168 m). The Palisades, rising vertically from close to the water's edge, are the margin of a sill of diabase, formed by the intrusion of molten material, which hardened into a great sheet. Slow cooling developed the columnar structure; uplift and faulting occurred, it is believed, at the close of the Triassic period, and centuries of erosion exposed the cliffs. A large part of the most scenic section is embraced in the Palisades Interstate Parks (c.81,000 acres/32,800 hectares), a chain of hilly, wooded recreational areas lying along the west bank of the Hudson between Fort Lee, N.J., and Bear Mt., N.Y. There are scenic roads, trails for hikers, campgrounds, and facilities for winter and summer sports.