THINK BURIED cities and archaeological digs, and you may not think of Annapolis right away. But local archaeological investigations have become a burgeoning activity in Maryland and Virginia in the last few years, and a continuing dig by a group called Archaeology in Annapolis offers a rich example of the kind of rewards the archaeological endeavor can bring. In this case, it's the reappearance of chunks of unwritten history long forgotten: the existence through much of the 1700s and 1800s of a thriving community of free blacks in and around the state's capital. Among the facts hinted at by the excavations, not so much unknown as unfocused-on hitherto, is the realization that the population of Annapolis in the 1700s may have been as much as a third black -- falling to one-fourth in the following century -- and that this population may have been substantially middle class rather than poor. The dig in a 19th century black neighborhood turned up imported teacups and saucers, along with the more familiar detritus of daily life and, mixed with it, discarded baby bottles and other trash that had drifted down from nearly modern-day houses with their foundations atop the old ones.

This particular dig is a joint venture of the Historic Annapolis Foundation and the University of Maryland, a partnership that nicely mirrors the double-edged value of archaeology in the context of a modern American city. On the one hand it's a reclamation of the history, or the many histories, that didn't get written down; on the other it's a textbook example, for the students on the dig and those in the classroom, of the practice of historical inquiry itself.

It's not so easy to demonstrate to students ranged in seats before a blackboard that there's more to what they're studying than a static cache of established and book-bound facts. It's easier in many ways to show them, to give them a hand in assembling the story, and in fact the popularity of such digs among college students and young volunteers is rising. In a country as young as this one, there's a natural tendency to see history as short and to think of vanished cities as buried beneath deserts far away; but really cities themselves are the best indications of previous cities' location. When the remodelers of the Louvre in Paris two years ago found themselves digging a 12th century citadel out of the cellar, the coincidence was no surprise to anybody. On the proper smaller and humbler scale, there's no reason to be surprised that the same is true of Annapolis.