Crater-like depressions and elongated grooves on a boulder at Grimes Point possibly date back 7,000 years or more. This pit and groove petroglyph style is believed to be the oldest at Grimes Point, and the depressions were made by striking the boulder surface with a rock. Another, more common petroglyph style, Great Basin Pecked, is thought to date from 1,000 B.C. to 1,500 A.D. and was made in the same fashion as the pit and groove style.