NEW YORK (AP).- The ship was buried as junk two centuries ago — landfill to expand a bustling little island of commerce called Manhattan. When it re-emerged this week, surrounded by skyscrapers, it was an instant treasure that popped up from the mud near ground zero. A 32-foot piece of the vessel was discovered in soil 20 feet under street level, amid noisy bulldozers excavating a parking garage for the future World Trade Center. Near the site of so many grim finds — Sept. 11 victims’ remains, twisted steel — this one was as unexpected as it was thrilling. Historians say the ship, believed to date to the 1700s, was defunct by the time it was used around 1810 to extend the shores of lower Manhattan. “A ship is the summit of what you might find under the World Trade Center — it’s exciting!” said Molly McDonald, an archaeologist who first spotted two pieces of hewn, curved timber — part of the frame of the ship — peeking out of the muddy soil at dawn o