A group of conservationists led by Andrew P. Hill camped at the base of Slippery Rock on May 15, 1900 and formed the Sempervirens Club to preserve the redwoods of Big Basin. Their efforts resulted in deeding 3500 acres of primeval forest to the State of California on September 20, 1902 to mark the beginning of the California State Park System.

California Registered Historical Landmark No. 827

Plaque placed by the State Department of Parks and Recreation in cooperation with The Conservation Associates, September 22, 1968.