Sound of Silence Trail
The Mesozoic Era lasted from about 250 million to 65 million years ago. It saw the evolution, terrestrial dominance, and eventual extinction of the dinosaurs.
For most of the Mesozoic, western North America was hot and dry, and the area around what is now Dinosaur National Monument alternated between desert dunes and broad river plains. The mountains that are here now had not been born, so this area was flat enough to be periodically flooded when sea level rose. Then in the Cretaceous (about 145 million years ago), a chain of volcanoes that had formed out in the Pacific Ocean slammed into North America. Mountains rose, seas were born and erase, and the land bent and broke. The climate turned warm and humid, and the sea advanced, flooding North America down the middle.
The rocks in this part of Dinosaur NM are almost all sedimentary. They were created when loose sediment like sand or mud was buried so deep underground that it became rock. Different sediments produce rocks of different strengths.
Many sites can been seen on the Sound of Silence trail, including the Entrada and Glen Canyon Sandstones. There is also the trace fossil-rich Chinle Formation. Trace fossils are fossils that don’t include bodies or body parts; for example, burrows and footprints are trace fossils. The Chinle includes burrows and trails of snails, insects, crayfish, and freshwater horseshoe crabs.
