All Ashfall skeletons are buried in a bed of pure volcanic ash. Volcanic ash consists of tiny shards of glass from broken glass bubbles. These glass bubbles form and then break apart during powerful volcanic eruptions.
Volcanic ash magnified 525 times.
The ash particles are small enough to have been breathed deeply into the lungs of animals when volcanic ash blanketed northern Nebraska 12 million (12,000,000) years ago.
At the Ashfall fossil site in northeast Nebraska, the ground beneath the soil looks something like this in cross-sectional view.
Sedimentary rock layers (strata) contain fossils that reveal clues to environmental conditions and the animal life of specific times in the past. The particles of sediment that make up the rock reveal clues about the environmental setting and how the rock was deposited.
An aerial view of a portion of the Ashfall Fossil Beds site. This photo was taken during the Park's development and shows a series of 6-meter sampling grids layed out on the newly-exposed surface of the ash bed. More »
Within this "Barn" view are the rhinos "Amy" and "Dr. Marie", a small three-toed horse (Pseudhipparion), a small deer-like animal (Longirostromeryx), a camel, and numerous scattered bones. More »