Some history on Angel Island...

After 1846 and the war between Mexico and the United States, Osio's title was disputed by various people, and a number of squatters took up residence on the island. In the early 1850s a quarry was developed on the island's east shore, and high-quality sandstone was carved out of the cliffs above Quarry Point for use at Mare Island, and elsewhere. San Francisco's original Bank of California, for example, was made of stone from the quarry on Angel Island. The quarry continued in operation until the 1920s, finally reducing the cliff to the present-day site of the parade ground at Fort McDowell.