Fossils are the remains, imprints, and traces of once-living organisms preserved in Earth’s crust. Fossils can be the remains of plants or animals (body fossils), or reflect their actions (trace fossils). Fossils are typically preserved in sedimentary rocks or, in a few unique situations, igneous rocks. They can be microscopic, as in single-celled animals (bacteria) or pollen; or macroscopic, such as fossils of leaves, petrified wood, shells of invertebrate animals, bones, teeth, tracks, feeding traces, coprolites, and burrows. Typical public conceptions of fossils are those of animals, especially dinosaur bones or teeth, or petrified wood.

BLM Management and Protection of Paleontological Resources

Management of paleontological resources on public lands is aimed at protecting vertebrate and other scientifically important fossils for the benefit of the public as a whole. BLM policy defines important fossils as including all vertebrate fossil remains, and plant and invertebrate fossils determined, on a case-by-case basis, to be scientifically unique. Abundance of these resources varies, with some geologic formations containing few or no important fossils and other formations known to commonly produce important fossils throughout the formation.

Congress passed the Paleontological Resources Preservation Act (PRPA) in March 2009. This Act supplements existing laws and guidance regarding paleontological resources on BLM-administered lands (e.g., FLPMA, BLM Manual 8270, and BLM Handbook H-8270-1). To address requirements in the PRPA, the BLM issued two IMs (“Casual Collecting of Common Invertebrate and Plant Paleontological Resources under the Paleontological Resources Preservation Act of 2009,” April 24, 2009 and “Confidentiality of Paleontological Locality Information under the Omnibus Public Lands Act of 2009,” June 5, 2009) (BLM 2009p; BLM 2009q).

Active Paleontology Permits, Monitoring, and Mitigation Efforts

Under current policy and continuing under PRPA, the BLM allows the collection of fossils with some restrictions, depending on the significance of the fossils. The BLM allows the public to collect common invertebrate or plant fossils in reasonable quantities using only hand tools (casual-use or hobby collecting). The BLM does not allow commercial collecting of fossils from public lands. Vertebrate and any administratively designated plant or invertebrate fossils may be collected only under certain conditions outlined in permits the BLM issues to qualified researchers. All fossils collected under a permit remain public property and must be curated in an approved repository.

The basic permit is the “Survey and Limited Surface Collection” permit. The BLM issues such a permit for reconnaissance work and collection of surface finds, and limits surface disturbance to 1 square meter. If the disturbance will be more than 1 square meter or require mechanized equipment, the researcher must apply for an excavation permit. Before it can issue an excavation permit, the BLM must prepare an Environmental Assessment for the proposed location. All fossils collected under a permit remain public property and must be curated in an approved repository.

In 2008, the BLM Wyoming State Office issued permits to 27 separate paleontological researchers/permittees to perform paleontological surveys and excavations in the Planning Area.

Potential Fossil Yield Classification

The BLM utilizes the Potential Fossil Yield Classification (PFYC) system to classify the potential to discover or affect important paleontological resources. The PFYC system is intended to help determine proper mitigation approaches for surface-disturbing activities, disposal or acquisition actions, recreation possibilities or limitations, and other BLM-approved activities. The PFYC system also highlights areas likely to be a focus of paleontological research efforts or illegal collecting. There are five classes of potential fossil yield, ranging from Class 1, “No Potential,” to Class 5, “Very High Potential,” for vertebrate or scientifically important paleontological resources. The Glossary includes a complete description of PFYC system classifications. Although granite and other igneous or metamorphic rock types are usually considered to be devoid of fossils, outcrops of these rocks can have fissure fillings, cave-like structures, sinkholes, and other features that could preserve important paleontological resources or information, so the potential is not zero; therefore, the BLM applies Class 1 to these rock types usually considered not to contain fossil resources.

As shown in Map 37, approximately 50 percent of the Planning Area is classified as Class 4 or 5 geologic formations, indicating a “High” or “Very High” potential for vertebrate or scientifically important paleontological resources.

Identified Paleontological Resources

The Planning Area is one of the most important areas in the northern hemisphere for the paleoecological study of global climate change. Recent and current scientific research is focused on the Paleocene‐Eocene Thermal Maximum (PETM) stratigraphic zone, which provides important data about paleoclimate in the basin. This important geologic contact between the Fort Union and Willwood formations in the Bighorn Basin and adjacent strata is an internationally known marker for data on paleoclimate, carbon isotopes, past global warming, and mammalian evolution. This important geologic zone is found in several locations throughout the Planning Area, including in the Clarks Fork Basin and Polecat Bench areas, south of McCullough Peaks, the Foster Gulch area, and several areas in the southern part of the basin. Research interest focusing on these areas is expected to increase over the next planning cycle.

The Planning Area is one of the principal areas in the U.S. for paleontological research on plants, dinosaurs, dinosaur track sites, early mammal evolution, and paleoenvironments, with a long history of producing many important dinosaur, mammal, and plant specimens.

The Brown/Howe Dinosaur Area ACEC, which includes the Big Al Quarry, includes extensive outcrops of the famous Jurassic Morrison Formation, a well-known dinosaur-fossil bearing deposit (refer to Section 3.7.1 Areas of Critical Environmental Concern). Coyote Basin, and other areas north of Shell, Wyoming, are large areas of exposed dinosaur‐rich fossil strata on public lands. The Red Gulch Track Site ACEC contains a world-class exposure of Jurassic dinosaur tracks exposed in the lowermost Sundance Formation. Scientists have expressed interest in building a geoscience museum in nearby Shell that would focus on the paleontological values of the area. The Big Cedar Ridge ACEC contains outcrops of Cretaceous Meeteetse Formation that produce extremely well preserved plant fossils in a 72-million-year-old ash bed. Natural Trap Cave, in the Little Mountain ACEC, is famous for producing fossils of Pleistocene-age mammals and other animals that fell into the cave and were preserved.

Important Fossil-bearing Strata in the Planning Area

Known fossil deposits in the Planning Area represent the past 543 million years, including the Paleozoic Era, virtually all of the Mesozoic Era (Age of Reptiles), and a major portion of the Cenozoic Era (Age of Mammals). Table 3–34 lists important fossil-bearing strata in the Planning Area, including the types of fossils within each strata, by decreasing geologic age.

Cretaceous strata in the Bighorn Basin have yielded important paleontological finds. In particular, outcrops of the Cloverly, Meeteetse, and Lance Formations produce dinosaur bones, while outcrops of the Thermopolis Shale and Mowry Shale produce the fossil bones of marine reptiles. The Meeteetse Formation has produced hadrosaur (duckbill dinosaur) bones and skin impressions in the Elk Basin area, and hadrosaur bones near Meeteetse. Fossil bones and teeth of the dinosaurs deinonychus and tenontosaurus have been found in many localities from the Cloverly Formation. The Paleocene/Eocene Willwood Formation occurs throughout the Bighorn Basin and is considered a world-class fossil resource in the field of mammalian paleontology and paleoclimate. These geologic zones are found in various locations throughout the Planning Area. Research interest focusing on these areas is expected to increase.

The Morrison Formation is known for its rich dinosaurian fauna (e.g., bones, teeth, skin impressions, eggshell, and trace fossils), and the Sundance Formation is important for its marine reptiles, trace fossils, and important invertebrate fossils.

Paleontological Resources Management

Special Management Designations for Paleontological Resources

Four existing ACECs in the Planning Area have been identified for their paleontological values  Big Cedar Ridge, Red Gulch Dinosaur Tracksite, Brown/Howe Dinosaur Area, and Little Mountain. In addition to these existing ACECs, four areas have been nominated as new ACECs based on their paleontological values  the Clarks Fork Basin/Polecat Bench West Paleontological Area, the McCullough Peaks South Paleontological Area, the Foster Gulch Paleontological Area, and the Rainbow Canyon Area. Refer to Section 3.7.1 Areas of Critical Environmental Concern for information on these existing and proposed ACECs.

Management Challenges

The BLM manages paleontological resources for the overall benefit of the public, which can include research, preservation, interpretation and museum display, and recreation. Management practices for paleontological resources are similar to cultural resource management, but regulated implementation is less stringent due primarily to the lack of specific legislative mandates and policies.

Scientific Use

Balancing the needs of scientific research and public recreation (including hobby collecting and onsite interpretation and development) against preservation of the resource presents a challenge for the BLM. The primary resource indicator for paleontological resources is whether there is a loss of characteristics that make the fossil locality or feature important for scientific use or public education and enjoyment. Natural or accelerated erosion, decay, improper collection, and vandalism can remove, alter, or damage characteristics that make the paleontological resource scientifically important or enjoyable to the public.

The BLM management of research efforts is relatively indirect and limited, primarily responding to requests from scientific researchers for paleontological use permits. At present, there are relatively few active permits for the Planning Area, and this situation is not expected to change in the future.

Public Use: Recreational Visits and Hobby Collecting

The BLM allows hobby collecting of common varieties of invertebrate or plant fossils and petrified wood throughout the Planning Area. However, this situation allows unrestricted collecting and could adversely affect certain resources that are unable to withstand collecting without some restrictions. Because of a lack of information, at this time it is not possible to identify specific areas where unsupervised hobby collecting could occur; further study might determine that there are such areas and that collecting activities can occur in those areas without long-term adverse impacts to the resource. Concentrating people at a developed site often increases adverse impacts to that site and the resource through increased vehicle and foot traffic and exposure to vandalism.

Regional Population Growth

Increasing visitation to public lands due to increased population could result in both intentional and unintentional damage to paleontological resources as a result of collection, vandalism, surface disturbance, and other depreciative behavior. Remote areas once protected by their distance from populated areas, are now within reach of hikers, OHV users, and nearby residents. In addition, paleontological resources in the Western United States, including sites where dinosaur bones have been found, are attracting visitors from all over the world to areas where they could adversely affect fragile resources through overuse.

Vandalism and Looting

Throughout the decades, public lands have been an easy target for thieves and looters, and the plundering and destruction of paleontological resources has become a highly lucrative business involving a network of looters and buyers in the United States and elsewhere. Most fossils taken from public lands are difficult to track to their place of origin.