A stone with the inscription “1775 M” – possibly carved by the famous outlaw Moses Doan – has been recovered from Buckingham Cave, ending a search that millions of television viewers witnessed on a recent episode of the Discovery Channel’s “Expedition Unknown.”

The Mercer Museum, operated by the Bucks County Historical Society, opens its new major exhibition, “The Doan Gang: Outlaws of the Revolution,” in its Martin & Warwick Foundation …