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 found 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 discovery 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 Tuesday. By Thursday, she and three colleagues had dug up the hull from the pit where a section of the new trade center is being built. A steep, hanging ladder trembled with each step down into chaotic mounds of dirt. People sank in the mud as they walked and grasped pieces of the historic wood for support - touching the centuries-old ship that may once have sailed the Caribbean, according to marine historian Norman Brower, who examined it Thursday. The ship likely got there because of the effort to extend lower Manhattan into the Hudson River in the 1700s and 1800s using landfill. Cribbing usually consisted of logs joined together - much like a log cabin - but a derelict ship was occasionally used. Another fascinating detail might emerge as work progresses: coins traditionally placed under a vessel's keel block as a symbol of good fortune and safe travels.