Initial monument marking the United States - Mexico border, dedicated at the site in Imperial Beach in June 1851. The marble monument was an obelisk about 20 feet in height on a marble pedestal. An inverted acorn on top symbolized the strength and stature of the California live oak tree. It was renovated, reconstructed at the site, and protected with an enclosure in 1894. The photo was taken by Herve Friend for Douglas Gunn's 1887 book, 'Picturesque San Diego'.