to graze sheep and cattle in the 19th century, the nearshore waters were also used for oyster farming. Also during the 1870s, the Central Pacific Railroad drew up plans to build a freight terminal on the island, but work was never begun. The first quarry opened on the southern flank of the island in 1892. Quarrying of the greywacke sandstone continued for 46 years until 1938, leading to another alternative name: Rocky Island. 20th century The quarrying operation continued in the early decades of the 20th century, with prisoners from San Quentin reportedly using the stone from this quarry to build the prison's south cell block (completed in 1913). During World War I the U.S. Navy considered leveling Brooks Island to build a battleship dock. By 1917, the Navy had determined that the existing Mare Island Naval Shipyard was suitable only for ships with a maximum draft of 30 feet, and that a new yard should be developed in San Francisco Bay to cater for ships up to 40 feet in draft. Starting with a list of 17 localities around the bay, the Navy narrowed this to four: Hunters Point, Alameda, Goat Island (now known as Yerba Buena Island) and Richmond–Albany. The navy considered four alternative plans in the Richmond–Albany area. Three of the four would have been at sites between Brooks Island and Point Isabel (to the east); the other plan proposed a site to the west of Brooks Island. However, the dock was eventually built at Hunters Point in San Francisco instead. The island also housed as a shrimp processing factory for a time. In the 1923, the U.S. Army Corps of Engineers was assigned to build the initial of a breakwater or "training wall" heading west of Brooks Island to protect the Richmond Inner Harbor and preserve the deep Harbor Channel connecting the bay with the Port of Richmond. Again, stone from the quarry at the southern tip of Brooks Island was used for this purpose. Over many years of subsequent repairs and extensions, the training wall grew to about and siltation built up sand flats of about along its length. The scale of quarrying accelerated from 1918. Sandstone from the Brooks Island quarry was reportedly used for the foundations of Treasure Island (1936-7), the Bay Bridge toll plaza (1936) and Berkley's Aquatic Park (1937). The quarry ceased operating in the 1940s. Following World War II there