Deep in the loblolly pine forest of this Army training base, small teams of archaeologists are digging up dirt and sifting buckets of soil to glean information about the continent's early people.

"The research potential here is great because it is such a large tract of land," said Deborah Keene, a University of South Carolina archaeologist overseeing digs at sites across Fort Jackson's 52,300 acres on the eastern edge of Columbia.

"We can look at populations over time -- from the earliest humans in the area right up to the historical period," she said.

Under contract with the U.S. Army, researchers from the university's Institute of Archaeology and Anthropology are investigating about 660 sites that could be significant enough for listing on the National Register of Historic Places.

The groups are working from initial surveys done in the 1980s and '90s that identified potential sites. Now, researchers use global positioning devices to determine the location and size of each site to help them gather information about the land's early inhabitants.

At one site miles away from the fort's noisy rifle and tank ranges, a half-dozen young diggers carefully lift shovels full of soil. A co-worker slowly sifts the dirt in a screened box and shakes it. It is hot, sweaty, tedious labor.

Elizabeth May, 24, smiled as she held up her find of the day: a rough, pockmarked shard of reddish pottery.

"It's a check-stamp made by a carved wooden paddle pressed into wet clay then fired," said Keene, explaining the lined decoration on the tiny fragment.

The researcher unfolded exacting survey charts of each site. The whereabouts of every item is kept in researchers' logbooks and repeated on tiny envelopes that hold the artifacts.

"That way, we have several records of everything that we have done," Keene said.

May's discovery probably dated from inhabitants of the Woodland Period, which ranges from 2000 B.C. to A.D. 1000, Keene said.

"These people would have been living there, as it was on high ground and within easy walking distance to water," she said. Several creeks run through the present-day military installation.

"They may or may not have been living there full time. . . . Maize agriculture really wasn't in full swing yet, so they were generally hunter-gatherers supplementing their diet with some domesticated plants," Keene said.

Anything found on federal land belongs to the government. To discourage potential illegal collecting, the archaeologists prefer not to make public the exact location of their work or the extent of their finds.

Mark Dutton, the Army's natural resource specialist at Fort Jackson, said researchers have found artifacts that could date back 10,000 years.

"We confer constantly with Native American tribes to make sure we don't have something that they consider to be of a religious or ceremonial nature," he said.

Although no such discoveries have been made here, researchers at Fort Stewart have found burial mounds. The Army installation west of Savannah, Ga., also has about 60 cemeteries and a pre-Revolutionary War British fort, said spokesman Rich Olsen.

"We have an archaeologist on staff," he said. "We have a pretty active program."

Dutton said he confers regularly with representatives of 10 Indian nations whose ancestors may have hunted or traveled around present-day Fort Jackson.

The land within the base's borders attracted settlers from various historical eras, he said.

"If it was a good hunting site for early Indians, it probably was a good site for early American settlers, too," Dutton said.

Deborah Keene, a University of South Carolina archaeologist, oversees digs along the eastern edge of Columbia, S.C. Elizabeth May holds her find of the day: a rough, pockmarked shard of pottery. "It's a check-stamp," Keene said, explaining its decoration.Rebecca Barrera, left, and Jamie Civitello, both of the University of South Carolina, work at a site near the Fort Jackson Army training base.