The Carnivores of Quarry 3, Agate Fossil Beds National Monument

Abstract

At the beginning of the twentieth century, in the remote upper reaches of the Niobrara River valley, paleontologists discovered an unbelievable trove of fossil bones eroding from two adjacent hillsides. Under these two “fossil hills” were buried entire skeletons of extinct animals that previously had been known only by fragmentary remains. Over the next two decades, leading museums of the day expended great effort exposing and then extracting whole portions of this bonebed for public exhibition and for research purposes. Many years later, scientists from the University of Nebraska–Lincoln reopened the old quarries to search for clues, long overlooked, that might explain why rhinoceroses, chalicotheres, and entelodonts had perished together millions of years ago at this particular place. In the process, they uncovered carnivore dens unrecognized by the first excavators. Today, the displays at Agate Fossil Beds National Monument lead visitors through the forensic evidence that discloses a sequence of events culminating in the demise of many hundreds of animals. The exhibits at the visitor center also include murals by artist Mark Marcuson and a diorama that uses full skeletal mounts, all illustrating the fascinating story of the Agate bonebed. In addition, the park is situated in a 3,000-acre preserve of shortgrass prairie and tells the story of rancher James Cook, who first noticed the bones in the 1880s, and his friendship with the scientists who came to excavate at Agate. Visitors can follow several trails to view the historic fossil sites, where wayside exhibits explain the paleontological investigations, and reconstruct the landscape of a dryland paleoriver valley and its animals, 22 million to 23 million years ago.