FREMONT, Calif. (KGO) -- A big construction project at the Calaveras Reservoir in the East Bay dug up more than 10 million tons of dirt and now scientists are marveling at what they've found.
For those used to looking at pipes and pumping stations, a fossilized whale skeleton is easy to miss at first.
"In the ground, it looks like everything else. I'm walking down a slope and my paleontologist says, 'Ohh, you're just stepping on it, ooh, right?'" San Francisco Public Utilities Commission spokeswoman Betsy Rhodes said. "'Cause they look like everything else, you have to be really trained."
But to the scientific eye, what started out as a few seashells found a little too far from the ocean has turned out to be buried treasure.
"Twenty million years ago, these fossils date from," Rhodes said.
There are over 500 fossils and counting, some perfectly preserved. "Scallops about the side of dinner plates, sea shells, snails, clams, mussels," Rhodes said.
That's only the beginning. Scientists have found bones and teeth from giant animals, including a serrated tooth from a Megalodon shark.
"The jaws are something you could almost drive a car through, it's that big and it was swimming here 20 million years ago," Rhodes said.
This is all happening in the midst of a huge construction project, but it's not slowing it down. By its very design, the project puts paleontologists right alongside building contractors. State law requires it that way.
"If we find a fossil that's in the way of construction, they'll quickly remove it or they'll stabilize it and protect it and come back at a later time when construction has moved on," Rhodes said.
It's all been part of the budget from the beginning.
"We did not expect to find this many, and when we started uncovering them we doubled our staff," Rhodes said.
Teeth from a Desmostylus, an extinct relative of the hippopotamus, have been found. Scientists are still unearthing the whale as well, with neck bones that could be 10 inches around.
"It's the combination of all these things that tell you what the ecosystem was like when that whale was alive, what it ate, what ate it," Rhodes said.
When the project is done, everyone hopes to find a museum put it all on display.