KILCHOAN, SCOTLAND—An archaeological team doing preservation work at the chapel of Mingary Castle on the west coast of Scotland has discovered markings scratched into the plaster walls. Made sometime between 1265 and 1295, the markings are thought to depict a local lighthouse, a ship, and perhaps the first letter of a name. "They've left messages on the wall and we're reading them," local historian Jon Haylett told BBC Radio Scotland. "It's pretty simple stuff, the sort of marks that would have been made by an illiterate man."