At 68 years old, Beatrice Goodwin wants to know where she came from, reports CBS News correspondent Trish Regan. Her grandfather, Clarence Tilley, was born in Portsmouth, N.H., in 1870, and she can trace her family as far back as her great-grandmother, who died the day Beatrice was born.

"I think sometimes the older you get, the more interested you get in who you are or who you were, where you came from," says Beatrice.

Now, a recent discovery in the small seaside town of Portsmouth may provide Beatrice with a crucial link to her past and at the same time, force this community to confront a largely forgotten part of its history.

During a routine construction project, workers stumbled onto a 300-year-old colonial slave cemetery — one of just two discovered buried beneath cities in the North. The other was found in Lower Manhattan in New York City, 15 years ago.

Archeologists Kathleen Wheeler and Ellen Marlatt excavated the Portsmouth site. From beneath these streets, they removed eight coffins and examined the remains of 13 people. They believe as many as 200 graves remain.

"It was kind of a social amnesia involved in that whoever this community of African Americans was, at some point they were forgotten and then the street was built over them," says Wheeler.

Slavery ended throughout New England by 1800 according to historian Valerie Cunningham. Sixty years later, it had become a distant memory.

"By the time of the Civil War slavery was not an issue in the North," Cunningham says. "The issue was in the South and so it was very easy to continue to demonize the South after the Civil War."

Geneticist Bruce Jackson is testing samples from those buried in Portsmouth to see if he can make a DNA link to residents like Beatrice Goodwin — and also to people living in Africa hundreds of years earlier.

"It's very likely they came from the Congo, or what's now the Republic of the Congo. And that is what we're focusing on," Jackson says.

If DNA results do eventually confirm a link between Beatrice and the slaves buried deep beneath Portsmouth, Beatrice says it will be a painful truth for her to recognize. However, it will also be a necessary journey — one that will give her children and grandchildren the answers she has sought most of her life.