Ashfall Fossil Beds State Historical Park is 2 mi. w. on US 20, then 6 mi. n. to 86930 517th Ave. The site's Hubbard Rhino Barn contains the skeletal remains of animals suffocated by volcanic ash nearly 12 million years ago. Many of the skeletons are fully intact, suggesting that hundreds of rhinoceroses, three-toed horses, saber-toothed deer and various camels, birds and turtles succumbed to slow suffocation from airborne volcanic ash. Visitors can view paleontologists performing excavation work and experience new fossil discoveries as they are carried out in full view.