New research has shed a little more light on one of America's longstanding mysteries: the disappearance of more than 100 colonists on North Carolina's Roanoke Island. The British settlers disappeared in 1590, three years after their arrival. Two hints persisted as to their fates: The word "Croatoan" was carved on a local fort, and "Cro" was carved into a tree, National Geographic explains. A series of recent finds, however, offer more detailed clues. When researchers examined two ink and paper patches on a map by the colony's governor, they found beneath one a miniature red and blue symbol, perhaps pointing to some sort of emergency shelter, the magazine reports. "Our best idea is that parts of Raleigh's exploration in North America were a state secret, and the map 'cover-up' was an effort to keep information from the public and from foreign agents," says a historian on the case.
Experts say "the only way (the colonists) could have survived" would have been to split up. Historians long believed that many went south to what was then called Croatoan Island, now Hatteras Island—but now researchers speculate that some colonists could have joined a tribe living to the west, at the mouth of the Chowan River. Researchers have been employing ground-penetrating radar in that area to test their theories, and they've found some previously-unknown structures—one of which could be a fence—underground. That would suggest colonists lived there, but it's unclear if the structures belonged to later colonists or the Roanoke Island crew. "We have to go in and dig some holes, I guess," says a researcher. (Read more Roanoke Island stories.)