Still Life in Ash

The Hubbard Rhino Barn was quiet except for the steady hum of fans running to keep air moving through the building.

Even when Nebraska’s sun bakes the hills of Antelope County, there’s a hush inside this steel structure 2 miles west and 6 miles north of Royal. Visitors lean on the railing and lower their voices as they look down into soft gray earth.

Six feet below the boardwalk, the outline of a rhinoceros emerges. Its legs are folded beneath it, ribs rising gently from the ash, skull intact and unmoved. Around it, other bones cluster close, as if caught in a moment frozen by time.

And that’s just it. They were.

About 11.93 million years ago, during the Miocene Epoch, a massive volcanic eruption in what is now southwestern Idaho threw ash high into the sky. The eruption happened along the hotspot track tied to Yellowstone. Winds carried the ash east, across the Great Plains, into the sediments that geologists call the Ash Hollow Formation.

It didn’t have to be hot to be dangerous. At Ashfall, the particles included tiny shards of volcanic glass, small enough to be inhaled deep into the lungs.

Back then, this was grassland and animals came to a shallow watering hole. Across much of the region, the ash layer is about a foot thick. Here, a low basin caught it and built up 8-10 feet deep. The proof of water shows up in pond turtles, reed-like stems and diatoms. What’s missing matters, too: no fish fossils, which suggests water that came and went. They didn’t all die at once.

Over days and weeks, the ash dust irritated lungs, weakened bodies and brought animals down one by one. Smaller animals died first. Medium-sized animals followed. The largest stayed longest, collapsing near the water’s edge and near each other, then slowly disappearing beneath continuing ash.

Under the microscope, the ash tells its own story. Tiny shards of volcanic glass, plant remains and mineral traces help scientists reconstruct the Miocene landscape and confirm that the animals here died over days and weeks, not all at once.

Kristin Dahl

National Geographic has called Ashfall Fossil Beds State Historical Park the “Pompeii of prehistoric animals.” Its rare, vivid preservation captivates visitors and scientists alike. The site is managed by the University of Nebraska State Museum, which oversees both research and public access.

University of Nebraska State Museum paleontologist Dr. Mike Voorhies discovered the site in 1971 when recent rainfall exposed a thick layer of volcanic ash high on the side of a steep ravine. Closer investigation revealed an intact baby rhino skull and lower jaw eroding out of the ash.

From that first skull came a deeper reveal: full skeletons of prehistoric rhinos, horses, camels, deer and more.

SINCE THE PARK opened in 1991, it has grown from a small building on the prairie into a working research site open to the public, with hands-on digs for kids who want to try it for themselves.

Spanning 17,500 square feet, the Hubbard Rhino Barn shelters ongoing excavations. From boardwalks above the bed, visitors watch interns and scientists uncover bones inch by inch.

Superintendent Sam Matson, who returned to the park more than 20 years after completing an internship there and then pursuing graduate studies elsewhere, recalled his early fascination with the fossil beds.

“I first came here as a fifth grader when it opened,” he said. “I was just blown away that something like this could be so close to where I grew up. It sparked my interest and set me on a path toward paleontology.”

Matson’s predecessor, Rick Otto, who recently retired, shaped much of what Ashfall Fossil Beds is today. “Rick wore many hats: from paleontology to carpentry, groundskeeping to marketing,” Matson said. “He left big shoes to fill.”

For many visitors, discovery begins at eye level. Children peer into microscopes at Ashfall Fossil Beds, connecting hands-on curiosity with deep time – an early introduction to science in a place where questions are still being uncovered, one layer at a time.

Jeremy Buss

Most fossil sites are closed off once the digging starts. At Ashfall, you can watch it happen.

“It’s not just about the bones or the science,” Matson said. “It’s about communicating science in a way that resonates with everyone, whether it’s a four-year-old or a visiting professor.”

One of the interns in the ash is Cannon Dunker, a University of Nebraska at Omaha student from near Blair. Dunker’s journey began young as well. “The first time I came here, I was six years old,” he said. “I even brought my dad’s hand pick, thinking I could dig fossils myself.”

Over time, his curiosity evolved into an intense interest in vertebrate paleontology. On a typical day, Dunker works inside a small rectangle of the fossil bed, patiently lifting ash layer by layer with scalpels, trowels and brushes.

“Each layer tells a unique story,” he said. “We find subtle features such as desiccation cracks – mosaic or mud-crack-like patterns indicating that water once covered this area – as well as insect burrows, ripple marks, even traces of algal mats that helped cement the ash into these thicker layers.”

Recently, Dunker and his fellow interns uncovered a fossilized dog track preserved in one of those algal mats.

“These are likely from extinct bone-crushing dogs,” he said. “We haven’t found their bones here yet, but discovering their footprints is exciting – they tell us that these animals were present at this site.”

Matson shared that excitement.

Today’s rolling prairie once held a thriving Miocene savanna. This low basin in Antelope County captured volcanic ash deeper than anywhere else in the region, preserving one of the most complete fossil assemblages in the world.

Jeremy Buss

“The bone-crushing dogs, or borophagines, were predators roaming this landscape millions of years ago. We found their tracks, but no full skeletons yet. Those footprints are a direct link to the predators that shaped the ecosystem. It’s rare to find evidence like this preserved so clearly.”

The footprints do what bones can’t: they suggest movement. Something crossed this surface on purpose, long before it became a graveyard. “It makes the ancient world feel more real,” Dunker said.

In the barn, signs of pregnancy are preserved, too, including a rhino with unborn young. It’s all part of a snapshot of life during the Miocene Epoch.

THE HEADLINER is the barrel-bodied rhino Teleoceras major, found here in remarkable numbers. With that many individuals in one place, scientists can look beyond a single specimen and ask bigger questions about herd structure, movement and why this basin became a mass grave.

Under the volcanic ash lie older fossils preserved in sandstone, showing animals that lived here over many years before the ashfall. Those remains are scattered, weathered and chewed, a contrast to the articulated skeletons captured in the ash.

The deaths of these animals weren’t sudden. The layering of the skeletons shows that smaller creatures died first, followed by medium-sized and then larger animals. Matson explained that many skeletons bear evidence of Marie’s disease – also known as hypertrophic osteopathy – a pattern of abnormal bone growth associated with extensive lung damage.

“The animals likely came to the waterhole sick, seeking relief, but eventually succumbed,” he said.

Researchers are still pulling stories from teeth. In a 2025 Scientific Reports study of Teleoceras major, Clark T. Ward and co-authors used isotopes in fossil tooth enamel and found evidence consistent with limited mobility. In other words, these rhinos likely stayed local instead of wandering long distances. The same chemistry can also hint at what they ate and what the climate felt like.

Bones emerge slowly from the ash, still arranged as they fell. Articulated skeletons, folded limbs and intact skulls remain frozen in place, a reminder that beneath Nebraska soil lies a rare and enduring record of loss, survival and the persistence of earth’s deep history.

Jeremy Buss

Matson sees Ashfall as more than a fossil site. He sees a place where big Earth forces become readable at ground level. The park’s restored mixed-grass prairie echoes the savanna that once stretched here.

Looking ahead, Matson dreams of expanding the park’s educational programs, hosting camps and field classes that bring geoscience alive for students. “We’re close enough to civilization to be accessible, but remote enough for adventure,” he said. “That sense of discovery is vital.”

Despite decades of study, much of the ash bed remains unexcavated. There are countless fossils and stories still buried beneath Nebraska soil.

As Dunker reflected on his time in the ash, he summed it up simply.

“This place is one of a kind. The Earth is always changing, so finding a site like Ashfall Fossil Beds is incredibly rare. Being here and uncovering the changes that transpired over millions of years in this part of the country – it’s the experience of a lifetime.”

For visitors willing to listen, Ashfall tells stories written in dust and bone, of ancient herds, vanished landscapes and the enduring pulse of life beneath the Nebraska sky.

PLAN YOUR VISIT

Ashfall Fossil Beds State Historical Park is open seasonally, typically May 1 through mid-October, and is closed from mid-October through April 30. Check current hours before you go.

During the annual winter closure, Nebraska Public Media’s free virtual tour offers a way to explore the Hubbard Rhino Barn and visitor center from home: nebraskapublicmedia.org/webxr/ashfallfossilbeds/