Made up of siliceous minerals, the eleven-million-year-old southern Mississippi petrified log was found intact rather than in fragments. According to Dr. Bobby Irby, then chairperson of the USM Science Education Department and coordinator of the acquisition, it was believed that the petrified artifact was covered in its location by a stream after having fallen into an ancient river, where it became waterlogged, buried in a channel, and fossilized. Dr. Irby noted the log to be sixty-five feet long, weighing over thirty tons. Biological examinations of the fossil wood indicated the log was a walnut-like hardwood. The petrified log or tree, more commonly known as the State Rock of Mississippi, was believed to be one of the largest Mississippi petrified logs at the time of its discovery in December 1986 by landowner William Thomas Johnson of Ovett, Mississippi, and it was dedicated on October 4, 1987.