Last week, workers at the World Trade Center site discovered a 30-foot section of an 18th-century ship , buried about 20 to 30 feet below street level. It’s a remarkable find, but hardly a first for New York. Since the late 1970s, hundreds of archaeological digs around the city have uncovered thousands of artifacts and structures — each of which have helped to shape our understanding of New York’s history. The Op-Ed editors asked 12 local archaeologists to share their most memorable discoveries.