If civic-minded locals are expected to know anything about prehistoric behemoths, it’s that the Columbian mammoths that once favored our parts aren’t dinosaurs. Millions of years passed between the last of the great dinosaurs and the ice age in which mammoths flourished. Yet when tourists visited the Waco Mammoth National Monument this past Fourth of July, one asked a familiar question: Which came first, the mammoths or the dinosaurs?