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April 19, 2014

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Revisiting Tule Springs’ ‘Big Dig’

Big dig

Forty years ago, when Tule Springs was 15 miles across mostly empty desert northwest of town, archaeologists found tantalizing clues that people may have lived in the Las Vegas Valley more than 20,000 years ago.

Further searches of an early human presence turned up nothing conclusive, but those researchers who cut trenches and followed bulldozers across the desert at the place now called Floyd Lamb State Park are calling for another look at a site that was once home to horses, camels, mammoths and sloths, and at least 10,000 years ago, human hunters.

Time is short, they believe, because growth has brought the edge of town within a stone's throw of the dig, and power lines are being built overhead.

The archaeologists, geologists and other researchers plan to discuss the need for action during a reunion Nov. 9-10 that coincides with the opening of an exhibit on the dig at the Nevada State Museum in Lorenzi Park.

"Unfortunately, the city is getting closer every day," Tule Springs Preservation Committee member Donald White said.

Volunteers such as White and other experts have returned to the site again and again, searching the dry washes for fresh evidence.

Almost 70 years ago, when most of Las Vegas was clustered around Fremont Street, archaeologists began to unearth animal remains at Tule Springs.

In 1933 Fernley Hunter of the American Museum of Natural History found a bit of charcoal associated with bones of extinct camel, horse and bison. Later that year Mark Harrington and Ruth Simpson of the Southwest Museum found more charcoal and bones from camels, horses, mammoths and giant sloths sticking out of the desert's surface.

Harrington and Simpson were hoping to find evidence that early humans had roamed the area 30,000 years ago, but the charcoal could not be related to people.

When Simpson returned to the site in 1956, she found a scraper that was radiocarbon-dated older than 23,800 years. But scientists could not establish that the scraper had been left by humans that long ago.

A 30-person team from New York, Nevada and California digging more than four months from October 1962 until February 1963 were able to prove that people used the site, said Margaret Lyneis, University of Nevada, Las Vegas archaeology professor emeritus, who was a UCLA graduate student in 1962.

"There is no question there were people out there, roughly 11,000 years ago," Lyneis said.

Geologist C. Vance Haynes led the "big dig," as it was known. Lyneis was the last scientist hired and the only woman scientist at the site 40 years ago.

The scientists are expected to swap stories and pose theories during their reunion next week. They are also hoping that further research at the site by today's experts armed with better detection methods might discover more clues to human existence in the valley's sand and gravel washed down from the surrounding mountains.

During the 1962-63 dig, Mark Levine discovered a scraper shaped by human hands that has been dated at 9,000 years old. The team also found flakes from toolmakers, burnt camel bones and teeth and mammoth jaws.

Haynes believed that if bulldozers dug deep trenches, the experts could read the layers of rock and gravel like the pages of a thick history book.

"A bulldozer driver leaned down to me one day and said, 'Why are you looking for the remains of people in all these dry lake beds?' " Lyneis said.

The answer to that question lies with Haynes; Willard Libby, who discovered Carbon-14 dating and won the Nobel Prize for chemistry in 1960; and Richard Shetler of the Nevada State Museum, who had arranged "the Big Dig."

Libby, who was developing the Carbon-14 dating technique in the 1960s, picked Tule Springs to test it because it held such promise of finding evidence of ancient human activity.

But the artifacts did not fit with the soils and rock where they were found, Tom Dyer, exhibit director for the state museum in Lorenzi Park, said.

"The valley filled rough and tumble," Dyer said, explaining that the action of water flowing across the Las Vegas Valley and the friction from stones could have polished some of the archaeologists' finds, making them look handmade.

Because scientists date objects by testing the rock and other matter around them, man-made objects cannot be dated with accuracy if they are jumbled among the valley's fill, he said.

It doesn't mean anything to find an arrowhead or a piece of flint, unless the surroundings spell out the context, Dyer said.

In this case, the area's jumbled rocks stopped the story in its tracks.

"People hold out their hopes, but if people were here 20,000 or 30,000 years ago, there should be flakes and some big chunky artifacts," Lyneis said.

"I'm not a conservative. I believe there were people here then. But how to prove it?"

A black flake of obsidian, possibly from a human-shaped tool, and 20,000-year-old bones found together in the sediments at Tule Springs during the 1962 dig were never conclusively linked, retired archaeologist Mark Rosenzweig said. There was no way to date the flake because archaeologists did not find any carbon-based material in the nearby compacted soils.

"The significance of the site is actually the science that was done there, not what they found," said Rosenzweig, a member of the Nevada-Archaeo Society and the Tule Springs Preservation Committee.

Scientists such as Libby and Haynes were major players in excavating sites. Together with geologists and paleontologists, the expedition leaders hoped to find early man's evidence.

"They brought it together in a conscious, coordinated effort, probably for the first time," Rosenzweig said.

Archaeology by nature is a matter of luck. Tule Springs was remote and hard to reach back in the 1930s, Rosenzweig noted. Harrington, even with a skilled eye, was lucky to stumble onto the original site, he said.

Now the site is easily accessible, as the presence of ATVs and remote-controlled airplanes illustrated during a recent visit. But finding anything significant has become more difficult because the site has already been worked so much.

"A lot of it is accidental discovery," he said.

The volunteers and experts coming together to ask that Tule Springs be preserved see the place as a great opportunity for educating children and allowing research to continue, perhaps at a center operated by the university in the near future.

"The past is the key to the future," said Helen Mortenson, an amateur archaeologist and Archaeo-Nevada past president.com