‘Right place at the right time’: Ranger naturalist describes finding fossils in Mokelumne River watershed


CALAVERAS COUNTY, Calif. (KTXL) – A scientific discovery millions of years in the making was uncovered in the Mokelumne River watershed in Calaveras County. 

Greg Francek, a ranger naturalist with the East Bay Municipal Utility District found a petrified forest in the summer of 2020. 

Hundreds of fossil samples discovered in Mokelumne River

“It really was a ‘right place at the right time,’ type of thing,” Francek said. “When I found the bones, I knew they were bones, but what I didn’t realize at that moment was I was actually looking at the bones of great beasts that had once roamed this landscape, millions of years before.”

Since then, scientists have recovered hundreds of samples from more than a dozen prehistoric species including the four-tusked gomphothere, two-tusked mastodon and the bones of giant camels and rhinos.

Francek says there’s other species of plants and animals which still need to be identified. 

“Fossil trees and plants and some of these leaves that we’re finding will give us an idea of what the landscape was like,” he explained. “The fact that we’re finding tortoise remains suggests that the climate was warmer.”

Petrified tree
Mastodon skull
Gomphothere recovery
Mastodon tooth
Tortoise shell
Mastodon tusks
Mastodon skull
Tapir jaw

Photographs courtesy East Bay Municipal Utility District

Each dig uncovers more fossils and more information about the area’s prehistoric past.

“We will continue to identify species and do geologic science and determine more what this landscape looked like between five and 10 million years ago,” Francek said.

Francek, who now manages the ongoing project, said he’s proud his discovery is contributing to science going forward.

“Helps us in one way to understand how climate change works,” he told FOX40. “The climate is always changing, it always has changed, and to understand those changes, especially in the American West is important to science.”

EBMUD has partnered with experts in paleontology and geology from California State University, Chico, who have established excavation sites over several miles of land along the Mokelumne watershed. 

The official study to date the land is still underway and more digs of the area are planned. 

The site is not open to the public, but you can take a virtual tour online by clicking or tapping here.


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