Secrets of a 400-Year-Old Village Are Disappearing Under Water

David Givens, an archaeologist in Jamestown, Virginia, is peering into a pit on a hot, cloudless afternoon in July. A year earlier, his team had been excavating at this spot and chanced upon a circle of bricks indicating a 17th-century well. He’s excited about what it might yield when they dig down into it: pieces of clothing and shoes, seeds, animal bones and other everyday items thrown away as trash, offering important clues to life in the colony.

Today, though, all that can be seen is a crab scuttling across the pit. “That’s not supposed to be there,” he says. ...