NEW YORK -- Researchers say a ship unearthed at the site of New York's World Trade Center predates American independence.
Columbia University scientists say they've determined wood used in the ship's frame came from a Philadelphia-area forest in 1773 -- two years before the start of the Revolutionary War and three before the Declaration of Independence.
Researchers say they've tentatively identified the ship as a Philadelphia-built sloop, a ship designed by the Dutch to carry passengers and cargo over shallow, rocky water.
After sailing for two or three decades, pieces of the ship were used as landfill to extend lower Manhattan.
A 32-foot piece of the vessel was found four years ago about 20 feet under a street during construction of the new One World Trade Center.