The rock is noted for its petroglyphs ("primarily lines, geometric shapes, and schematic drawings of people, along with writing, both verified and not.

Cotton Mather described the rock in his book The Wonderful Works of God Commemorated: Among the other Curiosities of New-England, one is that of a mighty Rock, on a perpendicular side whereof by a River, which at High Tide covers part of it, there are very deeply Engraved, no man alive knows How or When about half a score Lines, near Ten Foot Long, and a foot and half broad, filled with strange Characters: which would suggest as odd Thoughts about them that were here before us, as there are odd Shapes in that Elaborate Monument.

Hypotheses about the creation of the markings include: In November 1952, the Miguel Corte-Real Memorial Society of New York City acquired 49+1⁄2 acres (20.0 ha) of land adjacent to the rock to create a park.

Although Mather described these as deeply cut, a statement which has been repeated to the present day, early reports suggested that this was not exactly the case.

Even on the lowest part of the face, which alone does show evident signs of much wear, Mather's draughtsman, and Greenwood, and their next followers, were even less successful in making out apparent characters than have been some later observers.

Sewall in 1768 and Kendall in 1807 made definite statements to the effect that the greater part of the lines were so much effaced as to make their decipherment impossible, or wholly subject to the fancy.