In 1849, a crew building a railroad through Charlotte, Vermont, dug up strange and beautiful bones in a farmer's field. A local naturalist asked Louis Agassiz to help identify them, and the famous scientist concluded that the bones belonged to a beluga whale. But how could a whale's skeleton have been buried so far from the ocean? The answer-that Lake Champlain had once been an arm of the sea-encouraged radical new thinking about geological time scales...