Pleasant Grove Methodist Church in McLean, a historic landmark that was founded by freed slaves, has been sold to a buyer who intends to dismantle the structure and sell everything from altar to steeple to the highest bidders.

Plans by the new owner, Maryon Allen, wife of the late Sen. James B. Allen of Alabama, to demolish the little white clapboard church and sell it in pieces has aroused a storm of protest from county historians and former parishioners.

While efforts to save the church got under way over the weekend, it stood forlornly amidst ancient gravemarkers on its one-acre plot, its one room stripped of pews, its windows emptied of their stained glass and boarded up with plywood.

"It's really been raped," Bernard N. Boston, a member of the Fairfax County History Commission, said yesterday. The commission enrolled the 88-year-old church on Lewinsville Road in its inventory of historic sites in 1971.

The vacant old church was described by Elizabeth David, a history expert in the county planning office, as an "architecturally significant" example of the small, wood-frame chapels that were once numerous in the formerly rural county but which are now almost extinct.

Neither the county nor its history commission has the power to stop destruction of historic sites. When given advance warning, however, the commission has in the past been able to save many threatened landmarks by using persuasion and publicity to encourage preservation or stimulate purchase of a site by buyers who will keep it intact.

But Boston, other members of the commission and staff of the county's history and archeology section all said they were not told by the county's Department of Environmental Management that the church faced any danger. DEM issued a demolition permit to Mrs. Allen on Aug. 25.

However, Mrs. Allen's attorney, Lawrence S. Hoffheimer, said the permit carried the notation, "Okay, per historical," and was signed by Larry Coons, director of the Department of Environmental Management. Coons said yesterday that he was on vacation when the demolition permit was issued, and that a subordinate could have made the notation and signed his name. He said he could not immediately determine who that might have been.

Mrs. Allen, who served a portion of her husband's unexpired term in the Senate and now writes a weekly society column for The Washington Post, said she originally had intended to live in the church but changed her mind when she discovered that she couldn't get a permit from the county to expand the one-room dwelling.

"I'm a historical nut myself," said Mrs. Allen, a charter member of the Alabama Historical Commission. "This little building appealed to me very much, I wanted to save it . . . But you only have so much money.

"We were trying to disassemble it and place the beautiful parts in other buildings . . . I'm not getting rich."

Mrs. Allen said she purchased the church with two partners. She said their total investment, including purchase price, was $17,000.

Mrs. Allen acquired the church from William Watters United Methodist Church, a largely white congregation also on Lewinsville Road with which the black congregation of Pleasant Grove affiliated in 1967.

The new joint Watters congregation became the owner of Pleasant Grove and rented it out to the Peace Baptist congregation, but the church became vacant when Peace Baptist moved to Dunn Loring.

Officials of Watters were willing sellers, but they claimed they were misled by Mrs. Allen. "She misinformed me," said the Rev. R. W. McIntyre, the pastor.

John E. Strong, the chairman of Watters' board of trustees and the official who signed the closing papers last month, said, "It (dismantling and selling off the church) isn't what she said she was going to do."

Mrs. Allen disputed this yesterday, saying that church officials "knew I was going to take it down."

"They practically begged me to buy it" so they would have money to preserve the cemetery on the property, Mrs. Allen said. She said the church was "a wreck" when she first saw it. "It was pathetic, absolutely pathetic."

"All these people who are now screaming, they could have done something about this beautiful abandoned building, but they didn't. They let it sit there . . . I feel bad that we've done this, but I felt no one was interested in saving the things in the church that were really good, and that's what we're trying to do."

Mrs. Allen said she offered a stained glass window with the old church's name on it, the bell and the cornerstone to the Watters congregation, but that the offer was declined.

McIntyre and Strong, both of whom are white, acknowledged that they had been trying to dispose of the old church for some time.

It makes no difference to me," said McIntyre. "I have no historical connection with the church."

"I don't understand what all the hoopla is about," said Strong. "I feel very [angry] about the reaction. It (the church) was abandoned. It wasn't even being used."

But some black members of Watters who used to belong to Pleasant Grove said they were distraught over the sale and impending destruction of their old place of worship. "I'm definitely upset," said Frances K. Moore, whose ancestors, including Daniel Sharper, one of the freed slaves who founded Pleasant Grove, are buried in the adjacent churchyard, which Mrs. Allen did not purchase.

Some of the parishioners of the old church and nearby residents met Saturday night to organize a drive to save the landmark. Hoffheimer said some items from the church have already been sold, but that the stained-glass windows, pews and other objects are still in storage.

"Lots of the wood is worth money," Hoffheimer said. "It's tongue-in-groove pine. It's not an uncommon practice for restaurants to buy items like this."

While the church is on Fairfax County's historical inventory, the listing places no obligations of preservation on the owner. "Any power the history commission has is ex officio," said Elizabeth B. Pryor, chief of the historical and archeology section of the county planning office. "The commission has no legal clout. It can make a big stink, but it can't stop the destruction of a building on the inventory."

Nonetheless, Pryor said, "If we knew what was going on with Pleasant Grove, we would have encouraged the owners to put an ad in Historical Preservation magazine. The best solution is to publicize the place."