Works of "Research Collection"
Place Collected: Pacheco Pass
Place Collected: Ash Creek
Place Collected: US Highway 101
Place Collected: Twin Lakes Area
Place Collected: Panoche Valley
Place Collected: Syke Rock
Place Collected: Valley Ford
Place Collected: Mt. Diablo Mine (Diablo Mine; Ryne Mine)
Place Collected: Cazadero
Place Collected: US Highway 101
Place Collected: US Highway 101