By Published: Sept. 1, 2015

Patrick Mahaffy

A new campus exhibition explores a remarkable set of tools that ice-age humans used to harvest Boulder’s natural bounty.

In the spring of 2008, landscapers digging a fishpond in the yard of a Boulder home near Chautauqua Park heard an odd clank less than two feet down.

Probing further, they pulled up 83 pieces of stone packed tightly in a shoebox-size hole. The cache contained dozens of sculpted cutting tools, including stone knives, blades and flint scraps.

“I was speechless,” says Douglas Bamforth, the CU-Boulder anthropologist invited to inspect the tools by homeowner Patrick Mahaffy (pictured).

Subsequent research by Bamforth and others suggests the tools, made of quartzite or chert, were likely left behind some 13,000 years ago by nomadic hunter-gatherers wandering through what today is the city of Boulder — perhaps amid saber-tooth cats, camels, woolly mammoths, giant bears and other long-gone creatures.

Soon the general public will be able to behold the ice age relics in person: The rare cache of butchering tools, on loan from Mahaffy, will serve as the core of a new exhibition at the University of Colorado Museum of Natural History. “Unearthed: Ancient Life in the Boulder Valley” opens Friday, Oct. 9, and is expected to run for at least a year.

Besides tools, the exhibition will include replicas visitors can handle, a weighted bag giving a sense of their total heft and explanations of how scholars date ancient objects and make inferences about the people who made and used them.

“We have nothing like this at CU,” says anthropologist Stephen Lekson, the museum’s curator of archaeology.

The Mahaffy Cache is one of just a few North American artifact collections representing the nomadic Paleoindians known as the Clovis. They lived in North America toward the end of the last ice age, along with many now extinct animals, including the North American camel, woolly mammoth, dire wolves and giant ground sloths.

The implements found in Mahaffy’s Boulder yard were used for butchering and include elaborate two-sided knives the size and shape of salad plates, a tool like a double-bitted axe and sharp blades.

A blood protein analysis of the tools led by a researcher at California State University Bakersfield indicated some of the artifacts had been used to cut up ice-age horses and camels that went extinct around 13,000 years ago, as well as members of the bear and sheep family.

“These tools represented the height of technology 13,000 years ago,” says Mahaffy, who is CEO of Clovis Oncology, a Boulder-based biotech company named after a style of tools made by early North Americans.

Bamforth, whose work focuses on the archaeology of the Great Plains, evaluated the origin of the stone from which the tools were made and the wear and tear on them. He found that they likely originated in the Uinta Mountains in northeast Utah, and that the cache may have grown or changed hands in transit.

The cache was likely carried up the Yampa River in northwest Colorado and over a pass through the Gore Range into Middle Park, a high basin in the Rockies about 50 miles west of Boulder, he says. From there it may have been toted to the Colorado River headwaters and over a pass in or near present-day Rocky Mountain National Park, then to the Front Range.

“The tools are almost pristine,” says Bamforth. “The simplest explanation is that these people made the trip to present-day Boulder in one shot, perhaps in a month, without stopping much along the way.”

For reasons likely to remain a mystery, the tools were set aside and lost for more than 10,000 years. Now found, they’re available for all to see.

“It’s highly evocative to imagine these tools in the hands of ancient people chasing down prehistoric mammals,” says Mahaffy. “Making them accessible to the public will allow more people to be fascinated by them, and to wonder about the first humans wandering in this area.

Ice age cutting tools discovered in a Boulder yard

Photography by Glenn Asakawa