The more than 6,000 fossils include approximately 80 different types of animals found in Emery County, Utah. The specimens at this dig are thought to be about 100 million years old and are the first fossils found in this area from a span of time ranging from about 145 to 65 million years ago (the end of the Cretaceous period). These fossils will help shed some light on the great changes that occurred during this time period.

There have been some very interesting findings associated with these Cretaceous fossils. For example, the early dominant dinosaurs in North America during this period appear to have been the large, long-necked sauropods. But their huge numbers, combined with their huge appetites, caused them to essentially clear-cut the existing forests. The new flowering plants then moved in and took over, being fast-growing and capable of rapid colonization. These early flowering plants grew low to the ground as bushes and shrubs; the long-necked sauropods faded from the scene, apparently having eaten themselves out of a food supply. To take advantage of these low-lying plants, new forms of dinosaurs emerged and became dominant. These included such animals as the duckbills and the short, squat, horned dinosaurs.

Another finding concerns the ancestry of these North American dinosaurs: nearly all of the dinosaurs found at this site were first discovered in Asia. It is now thought that the North American Cretaceous period dinosaurs were the descendants of dinosaurs that first arose in Asia. This is the first evidence showing that these dinosaurs came from Asia, and most of these dinosaurs were present in North America by about 100 million years ago.