One is a striking Victorian farmhouse, hidden by rolls of green pasture and browning tufts of corn in Cedar Grove, far from the view of traffic or curious country neighbors.

Another is a tiny church of blue-painted boards and dreamy stained-glass windows, a piece of Darnesville's past situated next to new three-story colonial houses complete with grills and patios.

A third, once a home for pioneers, is a fragile shell of wood and mortar that can be found only by hunting down dusty road after dusty road in Poolesville.

Arguments to preserve properties such as these by designating them historic structures -- a decision that the Montgomery County Council will make for six properties in the next couple of months -- are as diverse as the eras they represent.

In Montgomery, a county whose countryside is rapidly being carved up by bulldozers, those debates have grown in substance and length since the county agreed nine years ago to identify all historic areas and buildings. A law was passed in 1979 to protect the sites.

"You don't have real hard-and-fast rules," county Planning Board Chairman Norman Christeller said about how the county decides what should be maintained. "What you have to have is good judgment."

A building is deemed significant based on its architecture, age and place in the development of Montgomery County. For instance, the ramshackle house in Poolesville is better known as Mount Nebo, a home fashioned in late 18th-century style and used by some of the early settlers in the western part of the county.

To some, the structure may be a relic best left to the demolition experts. To Bobbi Hahn, executive director of the Historic Preservation Commission, Mount Nebo is a bit of heritage that, because its owner wants to renovate, can remind others of what once was Montgomery.

"In a county that develops as rapidly as Montgomery, there is a real risk that the collective heritage of the county could be lost," Hahn said. "Look at Wheaton . . .or downtown Rockville, where the county building is. There's nothing left of what was the original business district. And we think people should know what their heritage is."

The county began surveying potential historic sites in 1976 and developed a list of 950 homes, churches and districts that planners agreed deserved more study before being designated as historic. The preservation commission, formed three years later, has been examining the sites.

After a building or area is recommended for preservation by the nine-member commission, the planning board must make its own recommendation. The County Council makes the final decision, as it will again after a public hearing Oct. 15 on the six sites in western and northern parts of the county.

Thus far, 105 of the buildings and districts, mostly in rural Montgomery, have been approved for such designation by the County Council, Hahn said.

Acorn Park, off Blair Mill Road, received approval as the site of the spring from which Silver Spring took its name.

The post office in Silver Spring, built during the 1930s, also was approved as an example of federal architecture during that era.

One building that is a familiar sight in Silver Spring -- the Little Tavern on Georgia Avenue -- didn't make the cut.

"It was decided that it wasn't a building of cultural significance," Christeller said.

If a building is designated historic, the owner cannot alter the exterior without county approval. As an incentive to accept this restriction, however, the county has agreed that the owner should receive a 10 percent property tax credit for any money spent on approved exterior work.

That same incentive is used in Prince George's County, where preservation commission members have the authority to designate sites without council approval.

Receiving a historic designation from a county does not mean the structure is listed on the National Register of Historic Places or that it is eligible for federal tax benefits. It simply means that the community or building is representative of a certain time and development in that particular county and should be saved, Hahn said.

The discussions that lead to those decisions often lean heavily on historical findings and individual interpretations of the significance of the building in the community. Christeller, who at times is at odds with the preservation commission's recommendations, said the planning board often has to weigh the historic significance against the need for development in the community.

One example of that balancing act occurred two months ago when the County Council had to decide whether the Falkland Apartments, located at 16th Street and East West Highway in Silver Spring, were historic buildings.

It first was believed that the three buildings that make up the complex were the first garden apartments in Montgomery County and were the first to receive FHA insurance. They were described as a "good American adaptation of English garden apartments."

When members of the planning board researched further, however, they found that the units were not the first garden apartments in the county, did not receive the first FHA approval and simply were not the best example of English garden architecture.

The solution? The council decided to preserve the corner building of the complex, a rather distinctive structure, and let the owners have the freedom to do what they wanted with the other buildings.

"At times, I have felt [the historical commission] was going too far," Christeller said. "One time, a building was recommended as a 'familiar visual symbol of the neighborhood.' Well, you can say that about the neighborhood gas station."

"Something can be a familiar part of a neighborhood -- and it can be ugly as hell -- but it doesn't make it as a historic building," Christeller said. "How many of these ordinary things do we preserve? We've never wrestled with that."