Brooks Island Regional Preserve includes both the of Brooks Island above the low-tide line and of the surrounding bay. The only public access to the island is via an East Bay Regional Park District naturalist tour. Brooks Island is a mostly flat strip of land extending from a round hill, named Jefferds Hill, which peaks at in San Francisco Bay, located just south of the Richmond Inner Harbor in Richmond, California. Originally named as Isla de Cármen by a Spanish explorer, the island appeared as "Brooks Island" on maps from 1850 onward. The eponymous Brooks has never been identified. It has also been called Sheep Island and Rocky Island at various times. The island was bought by the regional parks district in 1968, and was opened to the public in 1988. Access is now available through ranger-led guided tours. History Ohlone period On the island are the remains of several shellmounds left from prolonged occupation by Native Americans, most likely people from the Ohlone tribe, sustained by the abundant sea life in the surrounding bay. The park district's 1976 resource analysis identified the tribes as "Huchium [Huchiun] or perhaps Chochenyo", and speculated that as many as 15,000 people might have lived on the land over the course of 2,000 to 3,000 years. The first archeological excavation on Brooks Island was conducted by Nels Nelson of UC Berkeley in 1907. More systematic excavations of shellmounds on Brooks Island began in 1960 with the excavation of shellmound sites CCo-290 and CCo-291 on the northeast shore by George Coles of Contra Costa College, and Vera-Mae and Dave Fredrickson. Coles' excavation of the largest shellmound (d. 2015) during the 1960s, which produced carbon-14 dates of 1,700–2,000 years before present for the oldest materials in the mound. Coles estimated that the Ohlone occupation of the site may date back more than 3,000 years. His study found bones from cormorants, ducks and other waterbirds (but no pelicans). Marine mammal bones included harbor seals, sea lions, porpoises and whales. These early residents used atlatls and harpoons with bone points. Even though the mound showed evidence of large catches of fish, especially herring, there were no fishhooks found, indicating that perhaps nets were used. Mollusks such as mussels, oysters, and clams were a large portion of the diet. From CCo-290, Vera-Mae Fredrickson reported the excavation of two small, elongated, painted pebbles of fine-grained sandstone, one with a single