Mr. Luccketti, 66, chose his words carefully as he described the fruits of their latest work. “I’m trying to make sure that I say this correctly,” he said. “We have evidence from this site that strongly indicates that there were Roanoke colonists here.”

In Chapel Hill, N.C., on Tuesday, the foundation will reveal its findings and the theory that at least a few of the settlers moved inland to Site X. The announcement, along with separate findings from another excavation on a coastal island, is sure to stir excitement, but it is also likely to set off a new round of questions: Why would some of the settlers have split off to the inland site? Where did they go after that? And what became of the rest of the Roanoke colonists?

“We need to know more,” said Eric Klingelhofer, a vice president for research at the foundation and a history professor at Mercer University in Macon, Ga. “This whole story is a blank — a blank page, a blank chapter of history, and I think archaeology is the only way to come up with answers.”