Scientists hope to find 'identifiable cut marks' made by humans on the 13,600-year-old bones
                                
                                
                                    (Newser) -
                                    The well-preserved skull of an extinct mastodon has been discovered in Iowa. Officials from the University of Iowa's Office of the State Archaeologist said a 12-day excavation yielded "several mastodon bones," largely from the skull of the massive animal, belonging to the same order as elephants and...