From the plaque:
This pictograph, representing
a maze, is an outstanding example of the work of prehistoric
peoples. It, with 5.75 acres of land, was donated to Riverside
County as a county park on April 16, 1956 by Mr. and Mrs.
Rodger E. Miller.
Plaque placed by California State Park Commission in cooperation with Riverside County Board of Supervisors and Hemet Woman's Club February 9, 1957.