In downtown New York:

Several historians and archaeologists interviewed about the find said they did not have enough information to compare its significance with other discoveries in Lower Manhattan. In 1979, the walls of the Lovelace Tavern, which was built in 1670, were found during excavation for the building at 85 Broad Street that now serves as the headquarters of Goldman Sachs. And in 1991, digging for a federal building a block north of City Hall turned up the African Burial Ground that dates from the early 1700's. In both cases, at least some of the remains were preserved.

A battery wall appears on maps from the 1760's, but some archaeologists said they have a hunch that this wall may predate that one by as much as 60 years. Some say the discovery of the coin near the base dates it to at least the 1740's. There is no way to tell for sure exactly how old the wall is, but the archaeologists want to study the material in and around it.

And it's holding up subway construction...