What Workers Found Beneath a Los Angeles School… Scientists Say It Sat There for 9 Million Years

In most cases, the workers find old pipes, concrete foundations, or materials from the construction that were left behind. This is the type of work that was expected to be done during the renovation period in San Pedro High School in Los Angeles in 2022.

However, the workers found something that was totally unexpected.

Just below the ground was a dense layer filled with marine fossils. The remains had been sitting there quietly for millions of years.


At first, the discovery seemed like a small pocket of fossils, the kind that occasionally appears during construction projects. But as paleontologists began examining the soil, the scale became clear. The ground contained an enormous deposit packed with fossils. Researchers later estimated that millions of specimens were present, representing more than 200 different marine species.

The first indication of just how unusual this was came from the Daily Galaxy website. Follow-up stories on the same event were from the Los Angeles Times, which said this discovery could teach us something about ancient marine ecosystems that once thrived along the California coast.

In addition to the fossils themselves, the discovery told us something unusual about Los Angeles.

Millions of years ago, this area where the school is located was underwater.

Two Different Oceans Hidden in the Same Ground

But as the scientists looked more closely at the layers, they saw something unusual: the fossils were not all the same age. Instead, the site preserves two different chapters of ocean history.

The lower layer, from the Miocene, is nine million years old. Above that, a layer from the Pleistocene, which was formed 120,000 years ago, is found.

Finding both periods in the same location allows researchers to compare two very different marine environments. The Miocene ocean supported species that lived long before modern coastlines took their current shape. By the time the Pleistocene layer formed, marine ecosystems had already changed in many ways.

According to the Los Angeles Times investigation into the site, the fossil beds contain remains of a wide variety of marine animals. Scientists have identified fish, sea turtles, and marine mammals among the discoveries. Some specimens may even be linked to animals that lived alongside the giant prehistoric shark known as megalodon.

Another clue about the ancient environment comes from the surrounding rock. Many fossils are preserved in a material called diatomite. This rock forms from the microscopic shells of algae known as diatoms.

This aspect was discussed by Smithsonian Magazine under its article, "Construction Project Unearths Millions of Fossils Beneath a Los Angeles High School." Diatoms are known to thrive in nutrient-rich water, which means that the ancient ocean from which the rock came was a very productive ocean. In simpler terms, there was a lot of food in the water for a large network of ocean life.

When a Schoolyard Became a Research Site

The discovery has also sparked interest among people outside the scientific community, and it has affected the daily lives of the students in the school.

The days when learning about fossils was only possible by reading about them in books are gone. Now, students get the chance to work on actual fossils that were unearthed from beneath the school grounds. Experts from the Natural History Museum of Los Angeles County and California State University Channel Islands assist them in identifying the fossils.

News reports from outlets such as Fox News Lifestyle, and The Guardian describe how these activities allow students to experience scientific research firsthand. For many of them, the idea that their school sits on top of an ancient ocean has made science feel far more real.

For paleontologists, the site is also important for a different reason. Fossil finds tend to be in deserts or remote cliffs. Not this one. It is buried in a busy schoolyard in the middle of a large city.

It is a reminder that the people who cross daily can sometimes harbor evidence of a world that was lost long before cities were built.

In this case, the evidence of that world was quietly buried beneath a high school campus, waiting for some construction to uncover a forgotten ocean.