310 Million-Year-Old Tiny Footprints Found in Grand Canyon
Hundreds of hikers each day pass by the fallen boulder along the Bright Angel Trail in Grand Canyon National Park. It might otherwise go unnoticed except for the 28 indentations — sloping tiny footprints left behind by a small, reptile-like creature about 310 million years ago — that cover the rock’s expansive surface. Steve Rowland, ...