The area of Placerita Canyon was at one time occupied by the Tataviam Native American people and was included in the 1842 Mexican land grant issued for Rancho San Francisco. The park preserves the site of the first documented discovery of gold in California where in 1842, Francisco Lopez found gold flakes on wild onion roots under the “Oak of the Golden Dream”.
Check out this outside link for more about this location: https://en.wikipedia.org/wiki/Placerita_Canyon_State_Park