Founders' Rock, where the University of California campus is said to have been dedicated in April 1860, is a large outcrop located southwest of the intersection of Hearst Street and Gayley Road on the north side of campus. It consists chiefly of silica carbonate rock, a modified form of serpentine. The scratched faces, called slickensides, indicate that this piece of rock spent time in a tectonically-active zone, scraping past other rocks. According to Cal lore,it was also at this site that the name of the city of Berkeley was chosen in 1866.