The Glen Rose Trackway
The Glen Rose Trackway is a 107-million-year-old series of fossilized dinosaur footprints. Excavated from the bed of the Paluxy River in Texas, the trackway gives a picture of dinosaurs that in some ways is more striking than that offered by fossils.
Collected in 1938, the smaller prints are from a theropod, a dinosaur that walked on two hind feet. The larger ones were probably left by a plant-eating sauropod, such as Apatosaurus, the hind feet of which measured 3 feet in length.