The site is managed by the University of Nebraska State Museum and is open to visitors from early May through early October. In 1986, the Nebraska Game and Parks Foundation purchased the fossil site, leading to the creation of Ashfall Fossil Beds State Historical Park in 1991.
Expeditions in the late 1970s collected more than 120 articulated skeletons from the site. In 1971 erosion by heavy rains exposed a skeleton of a baby rhino, which was found by paleontologist Michael Voorhies. It wasn’t until the 1970s that the fossil beds were uncovered by scientists. There are reports of people finding fossil bones in the immediate area of the fossil beds going back to the 1920s, including a partial rhino skull found in a sandstone bed below the ash in 1953. History of the SiteĪshfall Fossil Beds is situated in rolling farmland drained by nearby Verdigre Creek. Otto, University of Nebraska State Museum. Pseudhipparion gratum is the smallest of five equid species from the site. The bones of large predatory mammals such as bone-cracking dogs are rare, but their presence is also known from trace fossils such as dung, tooth marks, and foot prints. Study of the 100+ rhinos indicates they likely represent several small herds with individuals of various ages and sizes, mostly females. Many of the rhino skeletons are preserved in three dimensions, showing their broad hippo-like bodies, and some have fossils of grass fragments in their mouths and bodies. They include a turtle and a large tortoise (demonstrating this area did not regularly go below freezing) several species of lizards found as gut contents in birds of prey a snake four bird species, including 40 crane skeletons, some with preserved feathers and gut contents two species of dogs a mole a mouse (also as gut contents) four species of camels a musk deer five species of horses and the rhino Teleoceras major, by far the most abundant animal found here. More than 20 species of animals have been recovered from the ash, with many others found throughout the sands deposited before the waterhole and eruption (although not nearly as well-preserved). Santucci, National Park Service.Įxcavations at the site show these intervals of death and burial, with the smallest animals at the bottom, then horses and camels a few inches higher, and finally the rhinos. Meanwhile, blowing wind deposited more ash in the waterhole, eventually covering the carcasses.ĭozens of fossil skeletons can be seen in the rock, left in place and prepared in relief. Their skeletons are the least damaged because there was nothing left to trample them. The last to succumb were a herd of rhinos, Teleoceras major (illustration)], that had congregated around the water source and eventually became too weak to leave it. Larger animals with bigger lungs lived longer but were killed by the effects of breathing the ash, which left telltale marks on their bones. Smaller animals were killed early on, suffocated by the ash their fossils are found at the bottom of the ash layer and are often smashed or broken up due to trampling by larger animals in the waterhole. Huge amounts of volcanic ash were ejected and spread in a plume across North America as much as a foot or so (30 centimeters) fell in the area around Ashfall. The volcano responsible was part of the same system that today is beneath Yellowstone National Park. At this time, a massive volcanic eruption occurred hundreds of miles away in what is now southwestern Idaho. 11.93 million years ago, there was a waterhole at the site, set within a broad savannah that was home to many kinds of mammals, some familiar in appearance, others not, and most from groups no longer native to North America. Geologically speaking, the fossil beds are within the Ash Hollow Formation, dated to around 12 to 5 million years ago within the Miocene Epoch.
The Fossil Bedsĭetailed study of the rocks and fossils gives a dramatic picture of the events that led to the fossil beds. Adult barrel-bodied rhino from the Ashfall site, one of forty currently exposed in the Hubbard Rhino Barn.
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