Some visitors who take guided tours around Walden Pond in Concord, Mass., walk away with more than a vision of Henry Thoreau's retreat.

They carry with them a false bit of history -- the wrong location of Thoreau's bean field, Bradley Dean, media center director of the Thoreau Institute in Lincoln, Mass., said.

While it might be just a bean field -- and a few misplaced "bean fields" are inevitable in piecing history together -- it matters when research contradicts beliefs, Dean said. And because historical perspectives can change, it is important that researchers support their facts and propagate the truth, whether it involves Walden Pond, or places like southwest Minnesota.

Dean spoke at a recent conference at Southwest State University in Marshall hosted by the Center for Rural and Regional Studies. The conference, "Draining the Great Oasis," was named for the center's recently published book, "Draining the Great Oasis: An Environmental History of Murray County." The book's micro-histories of one county probe the multifaceted relationship between human beings and their environment.

To make Walden Pond come alive, tourists often hire older local women as guides, a tradition established in 1938. These guides learn about the area from local history classes, Dean said.

"And since 1938, the rumor is that Henry Thoreau's bean field was back behind his house," Dean said.

Dean's research, gathered from Thoreau's journals and other documented evidence, puts the bean field elsewhere, along Walden Road. Yet, he is less successful getting tour guides to replace myth with fact than in gathering supporting evidence for the fact itself.

"People have it fixed in their heads that the bean field is back in the woods, and that's where the bean field needs to be," Dean said. "The difficulty then becomes, how do you propagate the truth into a larger community?"

Dean rounded up five local historians and took them to view the site, rather than reading them the supporting evidence and showing them maps.

"They became my spokespeople," Dean said.

While some might question the importance of a single literal, or metaphorical bean field, others consider such details vital, Dean said.

"You never know how important something is until somebody comes up and says, hey wait a minute," Dean said. "That's the wonderful thing about the infinite possibilities in the world. You simply never know, so you damn well better be careful."

Beyond Walden Pond, history sits in every living room in Concord and no one attempts to gather it, Dean said.

"Just oral histories, how valuable they would be," Dean said. "I wish somebody 50 years ago, 100 years ago was doing oral histories just so we'd know how people thought."

This might have saved the State of Massachusetts money. About 10 years ago, the state spent $230,000 testing the area generally believed to be the former bean field to scientifically establish its existence, Dean said. Tests proved negative.

"After I found out where it really was, I called them up and told them they were looking in the wrong location," Dean said.

Dean said part of his enjoyment of "Draining the Great Oasis" is the "eloquent case it makes for getting regular folks involved in reclaiming parts of their past."

Local people contributed to the book in interviews, as tour guides and in some cases as authors.

Southwest Minnesota historians face some of the same challenges as Dean with misplaced "bean fields," said Joseph Amato, a professor of history and of rural and regional studies at SSU who co-edited and authored one of the book's essays.

"Certain myths will wear themselves out in time," Amato said. "But when they do stick and propagate, sometimes they just remain."

He points to beliefs involving a scam in the early eighties that prompted him to write the book, " The Great Jerusalem Artichoke Circus: The Buying and Selling of the Rural American Dream."

"Even when people did pick up the book and read it, it made no difference to a handful of them," Amato said. "There's a residual group that loves its myths and clings to them. So, when you work in this field, you resign yourself to so many misplaced bean fields.

"Just creating a set of structures to interpret something, or a set of evidence that you think supports an interpretation, you put them on the landscape and give them life that they may or may not deserve. But you can almost rest assured, the next generation will turn them into realities, and if you have disciples, you can be sure they will elevate them."

For example, writer Sinclair Lewis asserted that every main street and small town are the same, Amato said. Some educators teach this idea without learning about the variety of small towns.

"So, a lot of the 'bean fields' are actually literary creations that are propagated across two or three generations," Amato said.

Perspectives also change through time, Amato said. Farmers who ditched and tiled southwest Minnesota viewed draining sloughs and wetlands as a positive move, and at the time, it was, Amato said. People got rich and agricultural production increased.

"But the newer generation, who come from the outside and don't live off agriculture and are caught by the world ecological distortions, of course challenge that it was good to turn a slough into a bean field," Amato said. "That's what is so fascinating about local history. At any one time there's a certain approach, or a certain set of ideas that are just partially true, and over a couple of generations they become the whole truth, or the truth anyhow that's told, and unless people are curious, or contradictory, or go out and look at evidence, that's the truth that remains."