From the longer Wikipedia page .
The Dighton Rock is a 40-ton boulder, originally located in the riverbed of the Taunton River at Berkley, Massachusetts (formerly part of the town of Dighton). The rock is noted for its petroglyphs ("primarily lines, geometric shapes, and schematic drawings of people, along with writing, both verified and not."), carved designs of ancient and uncertain origin, and the controversy about their creators. In 1963, during construction of a coffer dam, state officials removed the rock from the river for preservation. It was installed in a museum in a nearby park, Dighton Rock State Park. In 1980 it was listed on the National Register of Historic Places (NRHP).
The Wikipedia page on the town of Dighton is .