THE FUSE

A high school science teacher from Colorado has helped give paleontologists something they had never had before: a sequence of footprints likely left by a fully grown Tyrannosaurus rex. The trackway, described in a study in the Journal of Vertebrate Paleontology published Sept. 8, stretches about 23 feet (7 meters) across the Hell Creek Formation of southwestern North Dakota and dates to about 66.5 million years ago, shortly before the asteroid impact that ended the age of dinosaurs.