California Historical Landmarks in San Bernardino County
California Historical Landmark 774
Searles Lake Borax Discovery
Trona Road at Center Street (Roadside Rest Area)
John Searles discovered borax on the nearby surface of Searles Lake in 1862. With his brother Dennis, he formed the San Bernardino Borax Mining Company in 1873 and operated it until 1897. The chemicals in Searles Lake-borax, potash, soda ash, salt cake, and lithium-were deposited here by the runoff waters from melting ice-age glaciers, John Searles' discovery has proved to be the world's richest chemical storehouse, containing half the natural elements known to man.
Citation from California Office of Historic Preservation