The Morrison Formation is an Upper Jurassic, sedimentary geological unit that consists of sandstone, mudstone, siltstone, and limestone. Most of the formation is located in Colorado and Wyoming. In the late 1800s, Edward Drinker Cope and Othniel Charles Marsh were rivals in the <a href=”” rel=”noopener” target=”_blank”>Bone Wars</a> . Each of the two paleontologists used underhanded methods to try to outdo the other in the field, resorting to bribery, theft, and the destruction of bones. Their search for fossils led them west to rich bone beds in Colorado, Nebraska, and Wyoming. Colorado’s <href=”” rel=”noopener” target=”_blank”>Morrison Formation</a> is famous for being the most fertile source of dinosaur fossils in North America.