Construction At A Los Angeles High School Reveals Millions Of Prehistoric Fossils In A ‘Once-In-A-Century’ Discovery

With discoveries dating back 9 million years, researchers have unearthed the remains of saber-toothed salmon, whales, dolphins, and megalodons.

Wayne Bischoff/Envicom Corp.The fossilized mandible of a saber-toothed salmon found under San Pedro High School.

Construction work at San Pedro High School in Los Angeles has led to a startling discovery: millions of prehistoric fossils that experts are calling the “largest marine bone bed ever found” in California.

The excavation work began in 2022, and in the two years since, archaeologists have discovered three distinct fossil sites, each of which has a remarkable density of remains. The oldest fossils found at these sites are nearly 9 million years old and include the prehistoric remains of numerous animals like sea turtles, birds, fish, sharks, dolphins, whales, and megalodons. In all, the fossils represent more than 200 species, including some that had never been seen in southern California before.

Millions Of Prehistoric Fossils Are Found Under San Pedro High School

Austin Hendy/Natural History Museum of Los Angeles CountyThe campus of San Pedro High School.

As San Pedro High School was preparing for construction of new buildings, workers were shocked to uncover several fossil sites. One is a 120,000-year-old layer of shells from the Pleistocene epoch, and the other two are nearly 9 million years old.

The first of those is an 8.7-million-year-old bone bed from the Miocene epoch, containing the remains of a wealth of prehistoric animals, including fish and mammals. The other is an 8.9-million-year-old layer of phosphorous-rich rock revealing volcanic activity.

Now that construction on the school buildings is complete, scientists are able to dedicate more time to examining these fossil beds and showcasing just how important this discovery is.

Wayne Bischoff/Envicom Corp.Hundreds of limestone rocks were excavated from the site.

“There’s never been this type of density of fossils ever found at a site like this before in California,” Wayne Bischoff, director of cultural resources at Envicom Corp., told the Los Angeles Times. “It’s the largest marine bone bed found in Los Angeles and Orange counties.”

As Bischoff explained, this discovery is yet another clear reminder of what researchers have long known: the area that’s now Los Angeles was underwater for much of its geological history. Among the fossils was a large proportion of marine creatures, including the fossil of a saber-toothed salmon, seen in California for the first time as part of this find.

But according to Bischoff, one of the most fascinating elements of the discovery was the presence of shore materials, including sandpiper skulls and pieces of driftwood, which could serve as evidence of an “extinct island off the coast.” His hypothesis is that during the Miocene era, heavy storms washed plant and animal debris from an island, down into a submarine canyon where they were then sealed away by mud.

Austin Hendy/Natural History Museum of Los Angeles CountyFossilized vertebrae of dozens of small fish.

“After their experience on this site, [scientists] have started looking for other extinct islands,” Bischoff said. “It looks like there was a lot of islands that would form and then dissipate in the Channel Island zone.”

As geologist Richard Behl described it, “We’re kind of like detectives… We got to find clues and piece those clues together.”

Researchers Continue To Examine The Remains Of This Vast Marine Ecosystem

Following the completed construction, a majority of the fossils were relocated to California State University Channel Islands and the Los Angeles County Museum of Natural History, where researchers are conducting more thorough analysis of the finds.

Wayne Bischoff/Envicom Corp.Fossilized shark and dolphin poop found at San Pedro High School.

“We’ve moved away from just describing what we find, identifying new species, and making lists of things,” Hendy told LAist. “To really trying to understand how ecosystems function, how they’ve changed through time.”

“It’s a real window into what the geography of the oceans and land were at the time when this occurred,” Behl said. “Even though that seems a long time ago, that has real impact upon everything we got today.”

Wayne Bischoff/Envicom Corp.A collection of prehistoric teeth recovered from the site beneath San Pedro High School.

Even students at San Pedro High School expressed some excitement over the discovery. A few samples from the fossil deposits have been put on display at the school, allowing students to learn more about the history beneath their very feet.

“The fact that it’s here, and that we get to learn more about it, and it’s gonna spur more discovery?” said senior Taya Olson. “It’s just something that I’m really, really excited about.”

After learning about this shocking discovery beneath an L.A. high school, learn more about the prehistoric world and six of the strangest dinosaurs to ever exist. Then, see our gallery of 31 fascinating dinosaur facts.