Geologists have uncovered a set of 28 footprints along a hiking trail in Grand Canyon National Park. The footprints were left by a reptile-like creature and are cemented in a 310 million-year-old...
Geologists have uncovered a set of 28 footprints along a hiking trail in Grand Canyon National Park. The footprints were left by a reptile-like creature and are cemented in a 310 million-year-old...