NEW YORK — The Battery, a half-moon-shaped park at the southern tip of Manhattan, has long offered up clues about its former existence.
When a conservancy group dug up the old plaza to put in new landscaping last year, they found hundreds of oyster shells deposited there a century ago or longer by nearby taverns that dumped remnants of oyster dinners and other garbage along the shoreline.
But no one had come across vestiges of the original Battery, a wall of cannons erected in the 1680s at the confluence of the East and Hudson rivers to protect the nascent British colony.
Now city officials believe they may have stumbled on just that -- or, at the very least, part of a British fort that dates to the pre-Revolutionary War era.
The discovery was made last month in the northeast corner of Battery Park by construction workers excavating a trench for a subway extension underneath the park. In the middle of the night, they came across a 45-foot-long, 7-foot-wide mortared stone wall buried about 10 feet beneath the surface.
Alongside it, archeologists found a 1744 King George II halfpenny, a pewter medallion, remains of smoking pipes, and 17th and 18th century pottery.
For now, excavation has been halted as experts try to determine the wall's origins and find a way to bring it to the surface for public viewing. Based on the artifacts uncovered, archeologists believe it was built between the late 1600s and mid-1700s, which would make it the oldest fortification in Manhattan.
"It's incredibly significant because of its age and because of where it is and because of all the things that it might ultimately be proven to be," said Robert B. Tierney, chairman of the city's Landmarks Preservation Commission. "This could be where the Battery got its name."
Adrian Benepe, commissioner of New York's Department of Parks and Recreation, said the wall might be one of the city's most noteworthy historic finds in decades.
" 'The Battery' is a name repeated so often that it lost its meaning," he said. "These fortifications existed only in old etchings, but now it's there, it's tangible. To us, this is, relatively speaking, antiquity -- the equivalent of a Roman temple."
The discovery spotlights New York's often conflicted relationship with its past -- a mixture of pride in its heritage and a willingness to trade historical sites for ever-more impressive edifices. For much of the last century, the impulse to expand and modernize crowded out many historic buildings, including the beaux-arts Pennsylvania Station, which was demolished in the 1960s to make way for Madison Square Garden.
More recently, however, a preservation movement has taken root. When an African burial ground near City Hall was unearthed in 1991 during the excavation for a new federal building, the government bowed to public pressure and agreed to preserve some of the graveyard.
Still, progress often gets the better of the past.
Before officials realized the significance of the wall under Battery Park, workers apparently sliced through it with a backhoe, carving out a 7-foot-wide gap, according to an archeologist who visited the site.
A spokeswoman for the Metropolitan Transportation Authority, the state agency responsible for the subway expansion, said no officials were available to comment on the wall.
City officials remain hopeful that the damage was minimal.
"What's still down there is a large part of the wall, a significant portion," Tierney said.
For those enchanted with the city's history, the discovery has served as a potent reminder of what is still left to learn about New York's early days.
"People don't think there can be archeology in a place as urbanized as this, but there have been some marvelous things found in this city," said Joan H. Geismar, president of the Professional Archaeologists of New York City, who unearthed the hull of an 18th century merchant ship under the site of an office tower in Lower Manhattan in the 1980s.
Even before the wall under Battery Park was found, archeologists suspected that the MTA excavation might uncover some evidence of the various fortifications that were believed to exist there. But most expected that any find would be relatively minor, considering that the ground underneath the park had already been turned over multiple times during the construction of the Brooklyn-Battery Tunnel, a highway underpass, subway tunnels, utility lines and ventilation shafts.
"To find such a large piece of our history, relatively undisturbed, is remarkable," Benepe said.
What is now a 23-acre park was the site of the first European fortification on Manhattan, founded in 1623 by Dutch settlers, who named their community New Amsterdam. They erected a fort on the southern tip of the island and a low stone wall with cannons, according to the Battery Conservancy, a nonprofit group working to preserve the site and expand its cultural uses.