Deciphering the mystery walls of East Bay hills

Above San Ramon, on Rocky Ridge atop Las Trampas Regional Wilderness, there’s a rock wall where you might envision a hunter from 5,000 years ago hiding with a bow and arrow to ambush a deer.

“It’s my favorite spot on Earth,” said James Benney, one of a small group of explorershistorians who try to imagine the Bay Area as it was in the ancient days. “You can sit and watch the sunset across the bay, the hills glowing in front of you.”

In these moments, Benney said he could visualize life among the ancients.

“I appreciate the fact that they had this culture here that worked for 10,000 years,” Benney said.

Across the East Bay hills and throughout much of the Bay Area, Benney and his group have found rock walls, formations and alignments, many that could date to ancient times.

“Our mission is to explore, discover, educate, protect,” said Richard DeGraffenreid, who often teams up with Benney to explore Bay Area parks to locate ancient, historical structures. “We enjoy discovering a world inhabited by our local Native Americans.”

Some of the walls and rock formations have less farreaching origins. Spanish ranchers built many as property boundaries, they said. Chinese laborers built others when they cleared rocks to convert lands for agricultural or ranching use.

At a ridge at Sunol Regional Wilderness, what looks like a rock fortress could have been an outlaw’s hideout from the 1850s, DeGraffenreid said.

Many sites are a mystery, they agreed. “If only these rocks could talk,” is a saying shared by people curious about Bay Area history and its roots.

Here are some of the more significant finds:

Berkeley Mystery Wall, Tilden Regional Park:

What some call the “Berkeley Mystery Wall” is located on the ridge above Tilden Regional Park. At first sight, it looks as if its purpose could have been for ranching or as a property boundary. A closer look reveals a crudely stacked alignment. “There is nothing European or Chinese about the construction,” Benney said. “You look at it and you wonder, Who did it? How much work did it take? Why did they do it?”

Stone Corral, Morgan Territory:

“We believe this was an important Native American ceremonial site,” Benney said, because further exploration found a likely village site and yearround spring in the area.

Walpert Ridge rectangle, Garin Regional Park:

On the ridge here, rocks are positioned to form a rectangle on a westfacing slope, visible for miles. The wall is not sufficient to contain ranch animals. “With views across the South Bay, perhaps it was of ceremonial use,” Benney said. His group explored the area, and from a distance, scanning property that was offlimits, found “a rock alignment” that was connected to a possible ancient village site.

Clayton Ranch wall:

At Clayton Ranch, a nature preserve on the north side of Mount Diablo, a stacked alignment of rock extends for a few hundred yards, and includes a square enclosure.

“This one is a real mindbender,” Benney said. “The enclosure is obviously not corralling anything. What is it? We have no idea. Why would a western rancher take the time to build it, and if they did, for what?”

Sunol fortress, Sunol Regional Wilderness:

Along a subridge above the Alameda Creek canyon, they found a series of rock enclosures with short, wide walls out of rocks. It looks like a hideout for a bandit during the Gold Rush, DeGraffenreid said. The rocks were put together like pieces of a puzzle, he said, which showed a rare skill for historic walls and likely dates to a more recent past than many other rock formations.

Levin walls, Ed Levin County Park:

Several “extended rock alignments,” likely are boundary markers for historic ranchers, DeGraffenreid and several other historians believe.

Sierra Vista squiggly:

Ina mindboggling find at Sierra Vista Open Space Preserve above west San Jose, rocks are set in an extended “squiggly formation,” as Benney calls it, and has confounded all who have seen it. “What possible purpose was this squiggly?” Benney asked. “Someone made this squiggly wall for a reason. We just don’t know who or why. It looks real old. From what we can discern, there’s no connection to Europeans, Spanish or Chinese.”

Sunol circles: Stone circles, rock alignments and cairns found in the interior of Sunol Regional Wilderness, are likely ancient prayer sites, Benney said.

Montara’s rock throne:

On the westfacing flank of Montara Mountain at McNee Ranch, State Park Ranger Chet Bardo found a rock throne to take in a view of the Pacific Ocean. “I go up there and take it all in, and think about those who came before,” Bardo said. Benney said that he, too, has sat on that rock. “I try to imagine what it was like to sit here 5,000 years ago,” he said.

Benney lamented that few Bay Area residents have a sense of the ancient culture that preceded them. He suggested that park districts, schools and communities highlight and teach the history of the Bay Area’s first civilization.

“They should see what they are missing,” Benney said. “If people appreciated these sites, they would protect them.”

A longstanding dream of Benney, DeGraffenreid, researcher Robert Bardell and others would be to create a Volvon National Park in the East Bay hills to educate the public and identify and protect the sites. The new park, a vision more than a formal proposal, would connect parks, open space and watershed lands. Information is available at www.eastbayhillpeople.com.

Some 200 years ago, the Bay Area was populated with 10,000 or more people, DeGraffenreid said.

“The Volvon tribe ruled Mount Diablo, a sacred peak for all who could see it,” Benney said. “Their shamans and medicine women were important to all the tribes that came to Mount Diablo to pray, and conduct ceremonies, rituals and trade.. “The more we see out there, we keep finding growing evidence that these people were highly sophisticated. They had a culture, a society, a civilization. An appreciation for that is lacking in the Bay Area.”

“Our mission is to explore, discover, educate, protect. We enjoy discovering a world inhabited by our local Native Americans.”

Richard DeGraffenreid, who often teams with James Benney to explore local parks to locate ancient, historical structures

Richard DeGraffenreid / Special to The Chronicle A small rock fortress at Sunol Regional Wilderness looks like it was used as a hideout by the outlaw bandits of the 1850s.