Approximately 12 million years ago, a massive volcano in the southwestern corner of Idaho erupted and spread a tremendous blanket of ash over a large area. Much of this ash settled over the grasslands of northeastern Nebraska. Animals consumed the ash-covered grasses, and eventually they began to perish as a result of consuming this abrasive powder. Eventually these animals and their skeletons became fossilized, and this area is now the Ashfall Fossil Beds State Historical Park. Visitors to the Park's website will be delighted to learn that they can view a range of images and videos from the fossil beds, along with an excellent interactive skeleton map that documents the fossilized remains on site. Also, the "Ashfall Geology" site is uniformly excellent, and it includes aerial views of the site and details about the geological formations in the area. Finally, the "Ashfall Animals" area contains information about the paleontological finds, which include five horse species and a saber-toothed deer.