The Upper Missouri River Breaks National Monument (UMRBNM) encompasses approximately 375,000 acres of undeveloped land in north-central Montana. The monument is home to a great abundance and diversity of plants and wildlife, and is rich with cultural artifacts that speak to a long and exciting history of human occupation. The UMRBNM is also home to an amazing wealth of geological and paleontological resources that afford an unparalleled window into the ancient history of North America. It is in fact the rocks and fossils that arguably make the monument most unique, and the stark and beautiful landscape shaped by the erosion of ancient strata leaves perhaps the most enduring memory of the UMRBNM (just ask Lewis and Clark or Prince Maximilian and Bodmer).
This guide is designed for those who wish to explore the rocks and fossils of the UMRBNM in more detail. It is specifically intended to assist those charged with navigating and interpreting the UMRBNM for the visiting public, namely the River Rangers and other BLM personal stationed in the interpretive centers and campgrounds. The information included in this guide is focused along the Missouri River corridor, which extends for ~150 miles from the town of Fort Benton to the Fred Robinson Bridge. The first part of the guide is a general overview of the geological history of the region. This overview is followed by a more detailed treatment of the geology linked to specific river miles. The third part of this guide focuses on the rich paleontological history of the UMRBNM. Numerous examples of common fossils that the visiting public might encounter are illustrated and explained. The final section of this guide is devoted to specific localities in the UMRBNM where rocks and/or fossils are well exposed or particularly interesting/informative. These highlighted localities will serve as ideal field trips for visitors to the UMRBNM, and will enrich the overall educational experience for those specifically interested in learning more about the monument’s geological and paleontological resources. This final component of the guide is an on-going endeavor that will be updated and expanded in coming years.