The BYU Museum of Paleontology (ESM) is an official repository for fossils found on lands administered by the State of Utah, the Bureau of Land Management, and the National Forest Service. The fossil vertebrate collection is comprised of over 17,000 specimens ranging from Devonian fish (380 million years ago) to Pleistocene mammoths and cave fossils (15,000 years ago). Although the collections contain a variety of animals, our primary focus has been on dinosaurs from the Intermountain West. In particular, most of the field work has been focused on Upper Jurassic dinosaurs from the Morrison Formation, and Early Cretaceous dinosaurs from the Cedar Mountain Formation of Utah and Colorado.
Among the Morrison sites studied, the Dry Mesa Quarry in western Colorado has contributed the most to our knowledge of Upper Jurassic faunas, and is a large part of the collections here. Similarly, the Dalton Wells Dinosaur Quarry from near Moab, Utah, has been shown to be the most diverse Early Cretaceous locality known. Some dinosaurs from here are yet to be described and named.