A federal agency has objected to construction of a 15-story office building in the heart of Arlington, arguing that the structure's penthouse roof "would mimic the Washington Monument."

The 221-foot tall building, to be located on North Highland Street near the Clarendon Metro station, would be "a significant adverse visual intrusion" on the view from the Capitol's west terrace, the National Capital Planning Commission said in a letter to the Arlington County Board.

The letter said the planned Olmsted Foundation Building would exceed the federal agency's proposed height limits for eastern Arlington by 138 feet. The commission, which has no power to enforce its recommendations, has been waging a battle against high-rise buildings in Arlington for years, most notably in an unsuccessful lawsuit against the cluster of office buildings in Rosslyn.

The commission's criticism, a rare comment on a private building's design, puzzled architects and developers who said yesterday that the proposed structure, with its 1930s-style design, in no way resembles the Washington Monument.

"That floors me," said Hugh Mulligan, senior vice president of IB Realty, general partner in the Clarendon Metro Limited Partnership, developers of the project. "Everybody always criticizes the square boxes built in Rosslyn and then when you try to do something that could be a landmark, you get criticized."

The building would exceed Arlington's own height limits for the area by 68 feet. As a trade-off for exceeding height and density requirements, the developers promised to build a tunnel linking the building to the nearby Metro stop and to develop county-owned land between Wilson Boulevard and Fairfax Drive into a park.

Neighborhood groups have asked that approval of the project be delayed until the county has adopted a plan for development for the Clarendon-Virginia Square area. Arlington officials are hoping Metro will spur revitalization of the area.

"The main concern is over setting a precedent for other high-density development," said John Morland, president of the Lyon Village Civic Association, "We do not want the precedent for another Rosslyn being built in the area."

The proposed building would house the Olmsted Foundation, an endowment established by retired Maj. Gen. George Olmsted to provide scholarships for outstanding military officers. Olmsted, an 81-year-old Arlington resident, is chairman of the board of the Washington-based International Bank, which owns IB Realty Corp.

David Maudlin, an associate at the architectural firm of Martin and Jones, said yesterday the building was designed to conform to other buldings in the area built in the 1920s and 1930s when Clarendon was the premiere shopping district of Northern Virginia.

Mulligan said yesterday the developers are reconsidering some aspects of the building's design, but said it was unlikely that they would change either the height or the roof. The project now calls for two floors of retail space, with the remaining 13 floors reserved for offices. If the site plan approval process proceeds smoothly, Mulligan predicted construction would start by next summer. Several buildings, including a five-story office structure, will have to be torn down to make way for the building, Mulligan said.

"We felt we had a unique opportunity to make a significant contribution to the revitalization of the Clarendon area," said Mulligan, who noted that all the members of the Clarendon Metro Partnership are, like Olmsted, longtime Arlington residents.

Rob Baker, Arlington site plan review coordinator, agreed that the building's design is controversial. "Either you like it or you really don't like it," said Baker, adding that the building reminds some people of The Daily Planet newspaper building in Superman comics.

The building, with its distinctive design, would be ideal as the pivot of future development in the Clarendon area, Baker said. "We have always wanted signature, or landmark, buildings on top of Metro stations," he said, "This would be a positive design statement--a high-quality, high-visibility building that would indicate where Metro is."

Baker also defended the pyramid penthouse, which would house elevator and air-conditioning equipment. "Given the character and design of the building, a flat roof would detract," he said, "Peaked roofs don't have the same mass as flat roofs."