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The History and Archaeology of Yerba Buena Island - Discovery of Archaeological Site CA-SFR-04/H

Workmen constructing a parade ground for the Navy on the eastern end of Yerba Buena Island uncovered the remains of an Ohlone village-an archaeological site now known as CA-SFR-04/H. Workers removed the upper portion of the site, but buried the rest under layers of fill-inadvertently protecting it. This was before laws existed to protect archaeological sites, and no scientific studies were conducted.

Construction workers rediscovered CA-SFR-04/H during excavations for pilings for the original Oakland-San Francisco Bay Bridge and limited archaeological studies were done by UC Berkeley anthropologist L. L. Loud, but little is known of his findings.

A utility trench dug across a paved parking lot again uncovered remains of the site. Also in 1998, consultants under contract to Caltrans began augering to define the boundaries of the buried deposit.

2002 - 2004
Caltrans undertook archaeological excavations to recover data from the site before construction of the New East Span which could cause further disturbance.


The excavations uncovered an archaeological deposit made up of dark black-brown soil called midden. Midden is organic-rich sediments that accumulate on a human habitation site. It is often slightly greasy to the touch and contains charcoal, ash, and burned rocks from countless cooking fires as well as the remnants of many meals-including shell and animal bone. The midden at CA-SFR-4/H is about 25% shell. The deposit-up to a meter deep in places-sits on top of the original sandy dunes of the island. It probably accumulated from about 2,500 to 1,050 years ago, but the site may have been used intermittently up to the establishment of the Franciscan missions in the 1770s.

Rock and ash features and a possible cooking hearth were found, and hundreds of artifacts were unearthed and studied. The largest category of artifacts discovered was chipped stone, including dart, spear, and arrow points. Also found were stone mortars and pestles which would have been used for grinding and mashing various foods, and grooved stones that may have been weights on fishing nets. Shell beads and ornaments of abalone shell were also found. The animal bone discovered included ducks, geese, and sea otters which were hunted both for meat and for their thick, warm pelt. Thousands of fish bones were found in the site. Most of them were from three types of fish-silversides, rockfish, and surfperch. All of these could have been caught from the island's shore. Animal bone had also been made into tools such as the awl seen below which may have been used for making basketry.

Each small artifact and piece of bone, stone, and shell is part of a puzzle that, when assembled, will tell us more about the prehistory of Yerba Buena Island and the Bay Area.