Many of us still carry in our minds the image of a low-lying town with a church steeple as its principal vertical mark. It's part of our inherited visual landscape. A few such towns remain, but fewer every year. Mainly it's a nostalgic image.

Today in our big cities churches have become islands in seas of office buildings. But they are more important than ever in architectural terms. No longer central vertical marking points, they have become, willy-nilly, crucial elements of contrast, modest hand-touched reminders of the past, treasured artifacts, variations in the grid.

Western Presbyterian Church is a perfect example. Its architectural distinctions are indeed modest but the main thing is that the building still exists, a grace note of fieldstone gothic in a block of prepossessing institutional grandeur. The church sits on the southern side of the 1900 block of H Street NW, snug in the angle of a giant L-shape formed by the International Monetary Fund building--a heavy limestone-and-tinted glass structure.

The point of this comparison is not to put down the architecture of the IMF building, which in its way is distinguished. The point is simply to celebrate the tenuous survival of the little church and to suggest its symbolic and actual importance. Its setting in the shadow of the larger building is not a thing of unadulterated beauty but its presence there is a blessing. And this is the way, for good or ill, our cities are beginning to look.

A dozen years or so ago, when the IMF building was being planned, we were not so careful of these remnants. Initial drawings of the IMF building foresaw the demolition of Western Presbyterian. The organization needed space and, laudably, it sought to maximize the comfort and efficiency of its 1,500 employes. The result was the massive 12-story first-stage building with its soaring bottom-to-top, glass-covered interior courtyard--a prestigious package skillfully designed by the Kling Partnership of Philadelphia, and completed in 1974.

A second building with similar elevations and a mirror-image interior court was planned, to fill out the block. This was the wave of the future for the entire Foggy Bottom area, a place of large rooming houses and residential rows fast turning to new uses. The World Bank, the IMF, speculative offices and George Washington University all have primed the real estate pump of an area situated just west of the White House.

And the future is now, as the coach once said. The institutions have all but gobbled the area up--all but Western Presbyterian, and a few other churches, and a few scattered, more or less historic landmarks.

The main thing that developers failed to feed into their otherwise accurate large-scale calculations for change was the desire of parishioners to keep their churches. In this the story of the Western Presbyterian congregation is thankfully typical of what has happened elsewhere in the neighborhood, elsewhere in this city, and in other cities.

Western Presbyterian Church was founded in the 1850s. The present building was completed in 1931. It was designed by Norman Hulme, a Philadelphia architect. The land upon which the church sits is sky-high valuable--it is zoned for high-density office use. Consequently the pressures to sell were immense.

The congregation was pushed to sell from outside and inside: from the IMF, which made a generous offer to the church to build "almost anything we wanted almost anywhere," says John W. Wimberly Jr., the church's present pastor, and from the regional presbytery, which owns the land. The moral justification for selling was a luring vision of using the money to create a well-endowed urban ministry--to do good works.

The outcome of hours and hours and hours of contentious meetings was that the dwindled congregation voted to stay put "because we felt a church was needed here," says Elinor Martin, who attended Western Presbyterian as a girl and who, like most of the members, now commutes to the church from miles away. "I just thought the idea of selling the church for money was one of the worst things I'd ever heard of." As a result, the church stayed and the IMF extension, completed last June (and again skillfully designed by the Kling Partnership) took the form of an L instead of a square.

"There's no question about it, we're walking on the edge," says Wimberly, describing the church's efforts to serve its aging and scattered flock, to attract new members, and to provide spiritual sustenance to the vast new daytime population of office workers. "What we're planning to build on is the feeling of old Washington that is in the place, a kind of community feeling, a sense of having been here forever."

One does not need to be a parishioner to appreciate the simple courage of this decision, nor be an architecture critic to appreciate the benefits that tiny survivors such as this church give to our cities. In some areas, such as the bankers' alley along 19th Street, such small triumphs are all that is left to give a sense of history, texture and scale to the life of the street.