Clad in an orange construction helmet and vest, archeologist Jennifer Banister leaned against a wood-framed sifter and peered at a rusty nail she had plucked from a pile of dirt dug up on Boston Common.
Twirling the object between her thumb and middle finger, she determined it was probably from the 19th century. It was old — but not old enough.
“We’re looking for Revolutionary War-era material,” she said. “The British had encampments here. . . . We’re also hoping to find some Native American artifacts.”
Banister and archeologist Sam Rousseau, both from the Public Archaeology Laboratory in Rhode Island, on Monday began a project to uncover rare treasures from the city’s past.
Focusing on a strip of earth that lies underneath an asphalt path running between the Boylston Street MBTA stop and the Parkman Bandstand, the pair kept their heads down and their hands in the copper-toned dirt on a nippy autumn day. City archeologist Joe Bagley oversaw the excavation.
As Rousseau dropped shovelfuls of dirt onto the wire mesh of the sifter shaken by Banister, Bagley picked out small, jagged objects that the common person would probably pass off as nothing more than chunks of rock and debris.
For Bagley, however, it was history in his hands.
“We know we are on a good site,” Bagley said.
Bagley said there was strong evidence that Native American artifacts lay beneath the park’s surface.
A survey in the late 1980s of the area where Monday’s digging took place had identified a British troop encampment from the Revolutionary War. The camp was found directly over a Native American site that was between 400 and 1,000 years old.
Unfortunately, the path was laid down before any digging could be conducted, Bagley said.
But with the utility company Eversource now planning to run an electrical line down the middle of the pathway, archeologists got a new chance to explore the patch of land.
“Specifically in Boston Common, we really try to focus on the areas where we already know there are archeological sites,” Bagley said.
By midafternoon, researchers had discovered the nail, and several fragments of stoneware dating back to the 18th century. It wasn’t exactly what they were looking for, but they were getting there, one layer of soil at a time.
“We found some ceramics from the middle-to-late 18th century — some tin glaze, and some white salt glaze,” Bagley said. “We should be able to start marching back in time, hopefully hit the 17th century, and if we are really lucky, we will hit the Native American period underneath that.”
Artifacts from that time could include crushed shells left behind from consumption of food — such as clams, which were harvested by Native Americans in the Back Bay area centuries ago.
“They crushed up the shells just by walking on them and created this dense layer of shells. It’s kind of the calling card for the native presence in this area of Boston,” Bagley said. “We know there was a shell bed in here, but we are hoping it’s found preserved in the site.”
If researchers discover intact artifacts, rather than just fragments, along the path while digging this week, the Public Archaeology Laboratory will extend the project, before Eversource proceeds with its own.
“It could turn into a couple of weeks, depending on what we find,” Bagley said.