Twists and turns for Minnesota's oldest human bones

On the saving-old-stuff spectrum, William Jensen fell somewhere between collector and hoarder. He began unearthing arrowheads as a kid in the 1890s in the west-central Minnesota town of Browns Valley, on the South Dakota border.

To his large collection of Native American artifacts he added antique china and glassware, a birch-bark canoe, an old piano, stamp collections, license plates and yellowed newspapers. Neighbors considered his packed house a kind of museum.

But Jensen also had a day job — not a given during the Great Depression — managing a Browns Valley grain elevator. On an autumn day in 1933, he ordered haulers to move some gravel from the town pit to resurface the elevator driveway.

Matthew Granoski, who worked at another elevator, noticed a small bone sticking out of the freshly laid gravel. He handed it to Jensen, playfully quizzing his buddy's expertise: "Here, you geologist, what kind of bone is this?"

They soon discovered more bones on the driveway, including what looked like a human femur and a flint spearhead. Hopping into Jensen's car, they zipped to the gravel pit, where a hauler shrugged off their questions at his loaded wagon. Digging through his gravel with an old auto license plate, they found a stone knife and fragments of a human skull.

Scientists soon dubbed the discovery Browns Valley Man, judging the roughly 10,000-year-old bones to be some of the oldest, best-preserved prehistoric human remains ever found in North America. Experts said they belonged to a man between 25 and 40 who stood about 5-5. With about 40% of the skeleton intact, they could even deduce he was righthanded.

"Jensen's accidental discovery is a lesson in the value of paying attention to even mundane things — such as gravel," said Wendell Duffield, a retired Stanford-trained geologist who turns 80 on Monday.

After spending his career researching volcanoes for the U.S. Geological Survey, Duffield now lives on Whidbey Island off Seattle. But he grew up in Browns Valley and not only did he know Jensen and his family in the 1940s, his uncle married Jensen's daughter Eloise.

In a new, unpublished essay, Duffield suggests that Browns Valley Man's burial site — on a hill in the town's southeast side that once was an island in the ancient River Warren — was specifically chosen for "its relative safety from unwanted desecration." The Warren was a precursor to the Minnesota River and served as a giant drain pipe for massive Lake Agassiz when glaciers began receding after the last Ice Age nearly 12,000 years ago.

Browns Valley Man's more recent history also carries intrigue. Jensen invited University of Minnesota anthropologist Albert Jenks to Browns Valley in 1934, where the professor confirmed the bones were indeed ancient. In a scholarly 1935 write-up, Jenks guessed that Browns Valley Man was probably less than 12,000 years old.

More than 50 years later, scientists used carbon-dating technology called accelerator-mass-spectrometry to pinpoint Browns Valley Man's age at about 10,100 years old, according to tests of bone samples run at the Institute for Nuclear Science in New Zealand in the late 1980s. Other experts date the bones closer to 8,700 years old. Either way, Jenks won his over-under bet.

Jenks agreed to return the bones in the 1930s to Jensen, who loved showing off his skeleton to visitors. Shaking off pleas to donate the bones to a museum, Jensen "liked to have people come to the house and see" the bones, said his wife, Martha, in 1963.

But growing paranoid that someone might steal his gravel-pit skeleton, Jensen hid the remains in his basement around 1950 and told no one their whereabouts before his death in 1960. When Martha died in 1984, the Jensen daughters and their husbands scoured the basement. Rumors circulated that the bones had crumbled to powder. "Archaeologists tend to be pessimistic," said Scott Anfinson, a state archaeologist.

But after 37 years in limbo, Jensen's son-in-law Roger Weeks — Duffield's uncle — located the bones in a box in the basement fruit and vegetable cellar. Scientists rejoiced and the family transferred the remains to the anthropology department at Hamline University. Then a 1986 law clashed with the plans of anthropologists who wanted to keep the bones for further study.

The Native American Graves Protection and Repatriation Act spells out the need to return "culturally unaffiliated" remains to tribal leaders. In October 1999, 66 years after Jensen and Granoski found the bones, Browns Valley Man was quietly reburied on reservation land in northeastern South Dakota across the border from Traverse County.

At least one lesson was learned, Duffield reminds us: Always keep your eyes open — even when dealing with something as commonplace as gravel.

Staff librarian John Wareham contributed to this column.

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. His latest book looks at 1918 Minnesota, when flu, war and fires converged: http://strib.mn/MN1918.