Amateur sleuths on the dinosaur trail

Bones, footprints are uncovered in the Picketwire Canyon by a group of volunteers in their 70s and 80s

On a dry, chilly morning in the Southern Colorado grasslands, Bruce Schumacher led a group of AmeriCorps volunteers across the narrow, shallow Purgatoire River to an out-of-place bump in the landscape.

He pushed aside loose, reddish dirt with his hands, revealing a bone the size of a microwave oven — the limb of a sauropod dinosaur, said Schumacher, a paleontologist. The workers were surprised that the fossil was just sitting out on the plains, unguarded. Two of them joked about coming back at night to pull it out of the ground.

A two-hour ride down a dirt road, far from cellphone service or any other signs of human life, Picketwire Canyon is a dinosaur lover’s dream, largely because of hundreds of hubcap-size theropod and sauropod footprints pressed into a nearby layer of limestone, which abuts the river.

Schumacher, 48, who lives in La Junta, Colorado, is one of two field paleontologists employed by the US Forest Service. They are responsible for protecting and promoting dinosaur remnants scattered across the agency’s 193 million acres, primarily in the Rocky Mountain states.

The fossil site to which Schumacher led the volunteers is just one of many in the Morrison Formation, layers of rock lining 100-foot-tall mesas alongside the canyon. The site was discovered months beforehand, but because there were too many dinosaur bones and too few people to excavate them, it was reburied, for protection against thieves and the elements. For months, these bones lay undisturbed in the grasslands like buried treasure.

The two stewards of the Forest Service’s dinosaur bones are far outnumbered by the approximately 350 archaeologists employed to manage the traces of human life though the dinosaurs were around far longer than humans have been. “It all goes back to the laws and the homocentricity of those laws,” Schumacher said of the disparity.

The National Historic Preservation Act requires strict protection of human structures built 50 or more years ago on federal lands. With the requirement comes funding for archaeologists. While Schumacher and his Forest Service counterpart do team with academic researchers and museums, which provide some outside funding for protection of bones, there is no law that protects paleontological resources to the same degree.

So to get dinosaur bones from Picketwire Canyon to museums and scientists, Schumacher has developed a creative strategy. Twice a year, for a week at a time, these bones and footprints are uncovered by a group of about two dozen volunteers, many in their 70s and 80s, whom Schumacher has been training for the last 15 years. Because of the programme’s popularity, he no longer advertises it. Most of the volunteers have devotedly returned for every project and become a highly skilled team.

During their first week, in 2001, volunteers searched along the lower edges of the canyon walls that frame the valley for the bluish-white fossils that stand out among the brown and gray rocks and bright yellow grasses — “developing their bone goggles,” Schumacher calls it.

By the second-to-last day, they’d found nothing. So a volunteer took from his knapsack some petrified wood he had brought back to show his dejected partners. “That’s not wood,” Schumacher recalled telling the volunteer, who led the team back to where he had found the fossil.

There, over the next several seasons, the crew spent a week or two every year uncovering a Camarasaurus that they named Woody. In all, they pulled out about 15 per cent of the skeleton, now on display in the Sternberg Museum of Natural History at Fort Hays State University in Kansas.

Most of the volunteers are amateurs interested in paleontology, like a retired meat cutter, a retired secretary of an oil and gas company and a retired aerospace engineer. Some did their own bone hunting before they found the programme. Others were looking for opportunities for travel-oriented, post-retirement volunteer work; many have worked on similar archaeological projects around the world.

Ruthann White, 80, says she remembers racing back, goose-bumped, to what she referred to as her bone — a big, pork-chop-like pelvic bone — after months away. She has been part of 23 of the group’s 24 expeditions.

Bigger bones often require several weeks of tedious work, spread out over seasons, as the volunteers delicately coax them out of clay or mudstone. In October 2014, resting on his side in a safari hat, White’s husband, Allen, 80, carefully brushed dirt from a bone lodged in the Riverside Quarry wall.

Nearby, a mutton-chopped volunteer named Leroy Frazier, 62, (license plate: BONEDGR) carefully reassembled what looked like a football-size vertebra. “This is Sunday’s jigsaw puzzle,” he said, laughing.

Up the river from the quarry, on another day of prospecting, less seasoned volunteers pushed brooms across the dry limestone riverbed. Every couple of minutes someone uncovered new tracks made by theropods (bipedal carnivores whose prints show three talonlike toes) or sauropods (plant eaters that walked on all fours, leaving circular prints like potholes).

The footprints stretch for yards, disappearing and reappearing over the years, as floods and the river, itself, alter the landscape. “It’s always been called the longest track site in North America,” said Schumacher, adding that with recent discoveries by his volunteers, it may be the biggest collection of tracks in the world.

“Hey, Fat Boy!’
A Forest Service tractor scooped dust off the riverbed, leaving about six inches to be more gently removed by volunteers. Theropod tracks in the riverbed follow, and sometimes overlap, those of sauropods. For this reason, some at the site speculated that the tracks might be a game trail: theropods stalking their sauropod prey.

“This is where the big boy started getting in trouble,” said Sonny Fernandez, 77, resting by sauropod tracks that get deeper with each step and appear to be angling erratically left. “All those young ones seen him coming, said, ‘Hey, fat boy.’”

All signs suggest that this substantial trackway continues well beyond the berm of dirt where the volunteers stopped at the end of the week. And the group’s recent discovery of adult sauropod tracks alongside previously uncovered juvenile tracks lends support to an emerging theory that these dinosaurs travelled as a family.

But the prints still buried are almost certain to remain mysteries until the volunteers return. Fortunately for Schumacher’s mental health, he is in no rush to see the 150-million-year-old prints exposed. Still, he says, with more resou-rces, Forest Service could replicate the type of educational programmes that currently exist.

Before joining the Forest Service, he had worked on Sue, the best-preserved Tyrannosaurus rex ever found, as part of a team hired by the Field Museum in Chicago.
In the 23,000-acre Picketwire Canyon alone, Schumacher knows of a half-dozen substantive bone sites in addition to the covered track site. Some are untouched, and others have been only surveyed by the small groups of volunteers working two weeks each year.

“The real value comes from education and talking with kids learning about the history of the earth,” he said. “That’s not a commodity that you’re going to sell and burn.”