One of the most spectacular fossil deposits I’ve ever seen is Ashfall Fossil Beds State Historic Park, near Royal, Nebraska. We stopped there for a few hours today as we crossed Nebraska en route to Wyoming.
During the Miocene, a gigantic volcanic eruption in Idaho deposited several feet of ash in Nebraska. Animals living in the area were killed over a period of several weeks as a result of inhaling the ash, and their skeletons were beautifully preserved in the ash. When the site was discovered, it was decided to leave the fossils in place and build a museum over them, making a fantastic display.
The Ashfall deposit is dominated by the rhinoceros Teleoceros. This species is represented by both sexes and all ages, from fetal to adult. An adult and a baby are shown above (the baby is just above the adult’s shoulder). Here is another Teleoceros skeleton:
The adult Teleoceros were among the last animals to succumb to the ash, so their skeletons are generally the best preserved. The smaller animals died earlier, and their bodies were trampled by the large Teleoceros and dismembered by scavengers.
In addition to the rhinos, there are numerous other animals including three species of camels and five species of horses. One of the horses, Pseudhipparion, is shown below: