Three years ago, Chris Widga found bones and tools that had spilled out of a grave and down a slope.

Widga, a Kansas University graduate student in anthropology, was taking a break from final exams and hiking around Douglas County State Lake.

“I literally stumbled,” he says, “and was face to face with a projectile point.”

Erosion had loosened it and other things from their intended final resting place — a shallow pit about a yard in diameter.

The grave’s occupant was about 5 feet 5 inches tall and was buried with his legs tucked against his chest. He was at least 45 years old — an elder back then. He and his family likely roamed around hunting and gathering.

A limestone slab had been laid over the body and, through the millennia, the slab was covered by several feet of soil.

Excavating the site required permission. The nine members of the Kansas Unmarked Burial Sites Preservation Board, including four American Indian representatives, unanimously decided to excavate the site to prevent the removal of bones and artifacts by lake visitors.

With that and other permissions, Rolfe Mandel, associate scientist for the Kansas Geological Survey at KU, examined the soil around the find to establish a date for the grave.

“My gut reaction was that it was 4,000 to 9,000 years old,” Mandel says, “a pretty good guess.”

In a recent article in the journal American Antiquity, a team including Mandel; Robert Hoard, of the Kansas State Historical Society; and Mike Finnegan, at Kansas State University, reports that the bones were buried about 6,100 years ago.

Few burial sites discovered in these parts are that old. In fact, the site is among the oldest 1 percent ever found in the midcontinent, Hoard says.

The man’s lifespan was determined from dental wear. The pulp chambers of the teeth were exposed, so eating was painful, but there were few cavities.

Ancient farmers from, say, 2,000 years ago have lots of cavities and tartar buildup, but the coarser diet of the hunters and gatherers who preceded them helped keep teeth clean, Hoard says.

East of the Mississippi, in agricultural settlements, you find up to a 100 people buried together, but this grave was single occupancy. The plains were less settled back then, just as they are today.

Buried with the man was a deer bone. The projectile point Widga spotted was used not only to kill game but to skin and butcher it. A drill found in the grave was used to penetrate hard wood but not bone, according to Will Banks, of the Kansas State Historical Society.

This discovery is the kind that makes some imaginations leap, even if it causes shivers.

The naturalist Loren Eiseley, whose first academic job was at KU back in the 1930s, writes about a similar discovery in an essay titled “The Slit.”

While crossing the prairie on horseback, Eiseley came to a wall of clay and sandstone. He saw a crack in it no wider than his body. Eiseley writes that the slit looked “like an open grave.”

He wiggled in.

He had hoped to find a bone. Instead, he saw a skull staring at him. It belonged to a mammal, not a human.

Eiseley writes, “The creature had never lived to see a man, and I, what was it I was never going to see?”

The only rational reply to such a question is this: just about as much as the rest of us.