SAN FRANCISCO -- Construction workers at the future site of the Transbay Transit Center in downtown San Francisco on Monday unearthed a Columbian mammoth tooth and part of a jaw from about 11,000 years ago buried about 110 feet below ground.
A spokesman for the Transbay Joint Powers Authority, which is leading the project, called the tooth and partial jaw an "unlikely, extraordinary find."
The tooth was intact and well preserved, spokesman Adam Alberti said. The project's on-call paleontologist is assisting with the tooth and jaw excavation and will help move the ancient artifacts to the California Academy of Sciences in Golden Gate Park, where they will eventually be on display.
The jawbone is more deteriorated than the nearly 2-foot long tooth that still has enamel ridges preserved on the side and top of the tooth, he said.
Alberti said previous finds at the construction site have included human relics, mostly from the Gold Rush era in the mid-19th century when settlers were living in the area.
The tooth and jaw come from a much earlier time in Bay Area history when now-extinct species like the Columbian mammoth roamed the area. The closely related woolly mammoth had a furry coat and lived further north.
During the icy Pleistocene Epoch about 1.8 million to 11,000 years ago, the San Francisco area was a grassy valley where, along with mammoths, saber-tooth cats, giant sloths, mastodons, elk, tapirs and bison lived.
The ancient bones were found at the eastern end of the site between Minna and Natoma streets at First Street, which is under construction for the $4 billion transportation project. The first phase of the center is expected to be completed by 2017.