The mounds served many purposes.

“Shellmounds are created by my ancestors as ceremonial places and as burial sites,” said Corrina Gould, spokeswoman for the Confederated Villages of Lisjan and co-director of Indian People Organizing for Change. Lisjan is one of more than 40 native groups that call the greater Bay Area their home. As colonizers and settlers came to Northern California, they lumped these distinct indigenous groups into one. These days this larger group is most often called Ohlone.

Gould said innumerable burials were found in shellmounds: “Children buried with their mothers who had been lost in childbirth. Elders with babies.”

These bodies were then covered with layers of soil, shell and rock.

Growing bigger over time, the shellmounds transformed the flatlands by the bay waters into an undulating, awe-inspiring scene.

The shellmounds also served as an active space for the living.

“People would come and they would trade with each other, and they would have ceremony at the top of these mounds,” Gould said.

Archaeologists have found remnants of communal fireplaces, workshops and homes in the mounds. They were so central to community life that it seems there wasn’t even time for topsoil to build up or for grasses to grow, said UC Berkeley anthropology professor Kent Lightfoot.

Their height, sometimes taller than 30 feet, served as a focal point to navigate across the bay waters, or to communicate with other tribes.

“You could send signals to other people across the bay because you could see their fires,” Gould said, which could, among other things, warn groups about toxic red tide.

“There’s all of these things that are in these mounds that tell us this rich history of our people for thousands and thousands of years,” she said.

Gould is referring to remnants of daily Ohlone life, like the foods that sustained them: not only the mussel, clam and oyster shells that give the mounds their name, but traces of salmon and sturgeon, deer, and acorns from the ample oak trees.

How many shellmounds were in the Bay Area?

The San Francisco Bay Area was a popular place to live for Native Americans. Natural resources from both water and land were abundant here. The area from Point Sur in the south to the Carquinez Strait in the north was one of the most densely populated places for indigenous people north of Mexico, with roughly 10,000 inhabitants.

All these people meant a lot of villages, and therefore a lot of shellmounds.

But as colonizers and settlers came to California in the 1700s and 1800s, the native population was devastated. They were killed by newly introduced diseases, starvation and genocide. These killings were at times funded by the state of California and the U.S. government.

Native people began to disappear from their traditional land. When their houses of willow branches and tule reeds decomposed, the shellmounds were all that was left to mark where their villages once stood.

In 1909, a UC Berkeley archeologist named Nels Nelson counted 425 shellmounds around the Bay Area. He thought there had been many more, too, that were already worn away by water, time and development.

Corrina Gould believes that of the shellmounds Nelson documented in 1909, roughly four can still be seen, in such places as San Bruno, Fremont and Richmond.

What happened to the shellmounds?

Let’s take a look at the Emeryville shellmound as an example of a larger trend. This shellmound was the biggest one recorded in the Bay Area, more than three stories high and 350 feet in diameter, Gould said.

Demolition of the Emeryville shellmound. But if you look for the shellmound today, you won’t find much above ground.

In the late 1800s, developers sheared off the top to create a dance pavilion -- people were literally dancing on graves. At the base of the shellmound, they constructed an amusement park. Decades later the shellmound was leveled completely to make way for a paint factory. And in the early 2000s, the site of this once-busy native village became a busy outdoor shopping center.

This kind of destruction happened across the Bay Area.

But Gould emphasized that the shellmounds are still here, albeit underground.

“It's important for us to preserve and protect what's left,” Gould said. “Even if you as human beings can't see it on top, we know that the layers of our shellmounds go way deep underneath the land.”

The soil below where shellmounds stood is distinct. It’s a dark, rich color from organic material, with white pockets colored by remains of shells.

The rich soil from above-ground shellmounds was used to pave roads, fill in parts of the bay and fertilize gardens. Some of the human remains met similar fates.

Gould said the shellmounds are beneath landmarks that Bay Area residents pass daily: a Burger King in downtown Oakland, or Yerba Buena Gardens in San Francisco.

Many skeletons have been unceremoniously unearthed. Construction crews and archaeologists uncovered human bones as recently as the early 2000s, while building the Emeryville shops. Gould said most of these were reburied in an undisclosed location on the original site. In the past, remains were treated differently. Professional and amateur archaeologists sought out human bones and artifacts and sent them to universities.

UC Berkeley’s Phoebe A. Hearst Museum of Anthropology has more than 5,000 sets of human remains from the Bay Area alone. A “set” could represent the remains of one or multiple people, or even just an isolated component of a person, according to a spokesman for the museum.

Two years ago, Gould and other Ohlone people viewed the Hearst Museum’s collection of human remains.

“From the top of the ceiling to the floor there was all these trays with our ancestor remains up and down,” Gould said. “I'll never forget that experience that this institution is holding these humans, and for what purpose? And how many is too many?”

“They were the ancestors, you know, my direct relations.” Gould choked up as she spoke, describing her reaction after the visit: “I lay down in bed for three days and couldn't move. And it still hurts.”

What’s happening with shellmounds now?

Gould and other Native American activists are fighting to acquire land where the oldest Bay Area shellmound, nearly 5,000 years old, once stood: West Berkeley. The space is privately owned, and currently an asphalt parking lot at 1900 Fourth St., between the Fourth Street shopping corridor and the bay. The location has been designated as an archeological landmark by the city of Berkeley since 2000.

The landowners have sought to build housing here in recent years, but their proposals have been rejected by the city of Berkeley. While the owners have challenged the city, a judge recently ruled in favor of the city.

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Gould hopes eventually the land will be overseen by Ohlone and other Native Americans. She acknowledges this is just a dream right now, as the owners of the land are not willing to sell. But she said stranger things have happened.

Her vision is a space with native plants, a circular dancing structure for Ohlone ceremonies, and a 40-foot-tall mound with a spiral path and information about the Ohlone.

Gould and others regularly hold intertribal prayers here, on the current parking lot. Over her decades as an activist, Gould said Ohlone events have grown stronger, and the crowds have grown larger.

She sees this as part of a larger Ohlone resurgence: consulting for the Hearst Museum that houses bones of their relatives, reviving dance steps no one has followed in 100 years, and learning traditional languages — not spoken in generations — from tape recordings.