MONTPELIER STATION, Va. -- Sitting on the dirt floor of a century-old cabin, sisters Debra Arlene Mills and Donna Mills-Currie examine an animal bone they found in the ground.

They line it up with rusty nails, a chicken bone and buttons, and continue sifting through the soil. Across the small cabin, their father, Alfred Mills, 71, unearths a bead.

The sisters and their father traveled to Orange to spend three days digging in the dirt floor because their great-great-grandfather George Gilmore -- an emancipated slave who once belonged to James Madison -- built the cabin in the 1870s.

"To have a family that built something like this and find artifacts of ... my great-great-grandmother's life, it's pretty amazing," said Debra Mills, of Virginia Beach. "She could have been sitting here sewing."

The Gilmore cabin is about a quarter-mile from the Madison mansion. It was neglected until about 18 months ago, when state grants enabled Montpelier officials to complete a structure report and begin exterior restoration and stabilization.

The goal is to open the cabin to the public to show how emancipated slaves lived at the turn of the century.

"It's especially important for African-Americans," said Mills-Currie, of Colorado. "Our document of history is so sparse."

Alfred Mills provided archaeologists with a photograph that belonged to his grandmother of the cabin in its original form. From that, archaeologists rebuilt the front porch.

As one of the oldest living Gilmore relatives, Mills has a memory of spending a night in the cabin attic when he was young.

"I remember it 'cause it was such a miserable night," he said, adding that bugs flew around him while he slept.

He smiled as he looked around the cabin thinking of his grandfather as a child, playing with the wooden toys later found in the wall during an interior excavation. Marbles, buttons and straight pins also were found in the walls and floor, said Matt Reeves, Montpelier's director of archaeology.

"I found little artifacts a seamstress would have," Mills said. "I didn't think it would be this interesting."

The California resident has visited the cabin about 10 times but this is the first time he has done any digging.

"It's all about the family," Mills said, dusting off his hands, "and making sure someone gets some use out of it for educational purposes."

Once the cabin-floor dig is complete, Montpelier archaeologists plan to restore the interior. Originally used from the 1870s to about the 1920s, the restored cabin will look as it did during that period.

"African-American history, where do you go to research that?" Debra Mills said. "The cabin is so well-preserved - just sitting here in the dirt."