Evidence of prehistoric Native Americans has been unearthed in Central Texas at a secret excavation site.

A Texas Department of Transportation worker found multiple ancient campsites while working on a construction project in Williamson County.

The campsites date back some 8,000 years.

Jonathan Budd, an archeologist who works for TxDOT, says sites like these are sometimes found during work on their projects, but this one is unique.

"This in itself is extraordinary. This is found to be eligible for the National Register for Historic Places," said Budd. "We have significant archeological deposits here. For the last 7,000- 8,000 years you have multiple occupations like a birthday cake."

Even though archeologists are focusing on an area that's 70 by 30 meters, they believe the campsite is much larger. And for the most part, the artifacts they're finding have been remarkably preserved.

"For some reason, and we haven't really determined it yet, this was protected over the last 7-8,000 years.

Scientists are hoping to learn how and when early Native Americans utilized the prehistoric landscape to scratch out a living.

They're trying to keep the site a secret, but looters have already compromised a small section.

Steve Carpenter, an archeologist helping TxDOT with the dig, says looting can destroy a site.

"It has an adverse effect on our understanding of the entire site as a whole," he said. "People don't really know it's against the law."

Archeologists say the looters are after prehistoric tools like a bifacial stone that was uncovered or a stone burin, which was used to make holes through animal hides.

"They're fairly rare. That's the first one we've recovered from the site."

Even the dirt is valuable for archeologists.

"You can look at it through a microscope and figure out what kind of species of plants were burned."

The dig is expected to continue through the early part of February.