Cary Conover for The New York Times A 45-foot segment of cut and mortared stones, which archaeologists say was either a Colonial-era battery wall that protected European settlements in the south end of Manhattan or a piece of a fort that replaced Fort Amsterdam. Workers unearthed the wall last month while digging a subway tunnel in Battery Park. First came the excitement over the discovery of a Colonial-era fortification in Battery Park. Now it's decision time: What should the New York City do with this massive relic? City officials have conceded that the thick stone wall, which sits about...