U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
|Cody Field Office|
One of the more prominent specimens found on public lands in the CYFO is of a large carnivorous dinosaur or theropod known as Allosaurus fragilis, nicknamed Big Al. Big Al was excavated in 1991 by the University of Wyoming and the Museum of The Rockies. About 95% of the bones were recovered during the excavation. A cast of his skull is on display at the CYFO, and another cast is on loan to the Buffalo Bill Historical Center in Cody. Big Al was a juvenile and his skeleton was not associated with any other dinosaurs. Nineteen of his bones were broken or showed signs of infection which may have contributed to Big Al's death. The actual fossil bones of Big Al are located at the Museum of the Rockies in Bozeman, Montana.
Many different species of Jurassic-age dinosaurs have been unearthed from the Morrison Formation in the CYFO including: Allosaurus, Apatosaurus, Camarasaurus, Diplodocus, and Stegosaurus. Quite often, theropod teeth have been found when exhuming sauropod bones. The Sundance Formation has also yielded fossils of numerous marine reptiles including Ichthyosaurus and Plesiosaurus.
Although Jurassic-age fossils are important, younger Cretaceous dinosaurs are also found and excavated in the CYFO. The early Cretaceous Cloverly Formation has recently produced excellent partial specimens of Tenontosaurus, a relatively small ornithopod or "bird-hipped" dinosaur.
Recent research in the CYFO portion of the Bighorn Basin has centered around fossiliferous freshwater limestones in the Eocene Willwood and Paleocene Fort Union formations, and on an internationally known and scientifically-significant geologic contact situated between the Paleocene and Eocene epochs about 56 million years ago, known as the Paleocene Eocene Thermal Maximum or PETM. This stratigraphic zone in the Bighorn Basin produces important geochemical and paleontological data used by geoscientists to study mammalian evolution, worldwide extinctions and paleoclimate scenarios. Continental PETM sites are rare, and the Bighorn Basin is one of the best PETM localities in the world.
Survey & Excavation Permits
Paleontological Resource Use Permits authorize collection of scientifically significant fossils from BLM public land by qualified scientists, researchers and consultants. Institutions currently holding excavation permits in the CYFOinclude the Smithsonian Institution, Project Exploration and the University of Chicago, the Virginia Museum of Natural History, the University of Michigan, and Casper College/Tate Museum, among others. The BLM Wyoming State Office also issues permits to qualified paleontological consultants working on projects on federal lands. Scientifically significant fossils are defined as all vertebrate fossils and their tracks or traces, and some invertebrate or plant fossils identified as rare or important by the scientific community. Scientifically significant fossils may not be collected by anyone except holders of a BLM-approved permit authorizing such collection. Two types of permits may be issued by the BLM to qualified paleontologists or paleontological consultants:
Collection of Common Invertebrate and Plant Fossils
Visitors to BLM public lands can enjoy and collect reasonable amounts of common invertebrate fossils, such as clams, snails, cephalopods/ammonites, trilobites, and common plant fossils, such as leaf impressions, without a BLM permit. Petrified wood can be collected for personal use only (not for commercial resale) — up to 25 pounds each day, plus one piece, but no more than 250 pounds in any calendar year (43 CFR 3622). These materials must be for your personal collection and cannot be sold or bartered to commercial dealers. There are other laws regarding collection of petrified wood and some lands may be closed to hobby or casual collecting of fossils, so it’s a good idea to check in with the CYFO prior to collecting. On private lands, fossils may only be collected with the permission of the landowner.
For more information about the fascinating paleontology in Wyoming’s Bighorn Basin, please visit the following websites:
For more information about paleontology on BLM public lands, including information about education, permitting and collecting fossils, and about the new Paleontological Resources Protection Act (2009), please visit this website: