The oldest caves in the United States may be more than two millennia old, according to a new study.
The oldest known cave in California, the Maquokoetas, is in the Santa Clara Valley, where it was first discovered by a group of archeologists in 1856.
It was a “beautiful and unique discovery,” the team of researchers said in a news release.
“The Maquogetas are one of the few sites where there are still traces of ancient sediments and sediments from the beginning of the Mesozoic era,” said lead author Jennifer Schott of the University of Washington.
“It is very rare for these caves to survive in such a remote location.”
Researchers believe that a cave near the base of the Santa Monica Mountains was the site of an early civilization.
Schott, a geologist, has been excavating caves at the site since she was a teenager, and has documented the presence of artifacts dating back at least 4,000 years.
“This is a remarkable site that we have never seen in the history of the San Francisco Bay Area,” she said.
“We know it is a burial site for at least 3,000 people who were buried there and it was probably a burial ground for a very large number of people, including a large number who were women,” she added.
Schott and her colleagues recently returned to the site after spending six months working with the Santa Cruz Archaeological Society.
They’ve excavated about 1,000 cubic yards of sediment from the cave, and found about 10,000 artifacts, including pottery, arrowheads, animal bones and other artifacts.
“It was very rare that you would find this many pieces of material in a single site,” Schott said.
The team also found artifacts dating to the last 1,300 years.
These include stone tools, wooden tools and some pottery.
The team hopes to further explore the cave and to determine what its people did there.
“We think it was a very sophisticated society,” Schot said.
Schot and her team plan to expand their research into the cave’s history and what it means for the environment.
“What we are finding is the first time in the area of modern-day Santa Cruz is that people lived here for a relatively long period of time,” she told ABC News.
“So we are not just looking at the cave as a place for people to die.
We are looking at how these people were able to survive and thrive.”