Geologic Timescale and Paleogeography
Nebraska During the Cenozoic Era
The image above is a reconstruction of life around an ancient waterhole in northeast Nebraska during the Miocene Epoch (approximately 12 million years ago). During the Miocene, a volcanic eruption in Idaho generated huge quantities of ash, which was then carried by the wind to Nebraska. This volcanic eruption quickly buried northeastern Nebraska in several feet of ash, thus creating a world-class fossil site known as Ashfall Fossil Beds. Fossils include complete and articulated skeletons of large mammals, birds, and turtles, as well as seeds of grasses and trees.