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UMW Professor Co-Authors “Roadside Geology of Montana” Guidebook

July 13, 2020

Dr. Robert Thomas is a Professor of Geology in the Environmental Sciences Department at the University of Montana Western and co-author of "Roadside Geology of Montana." The publication is a revised second edition of the original book that was released over 30 years ago.

The book is a complete guide to the geological history of Montana and is designed to be utilized from the state’s many roadways. Whether you are a professional or a curious traveler, this book is intended to be used by anyone fascinated by the geology of the Big Sky state.

“No other place in the world has such amazingly diverse and well-exposed rocks with such dramatic stories,” the description states. From the Yellowstone Caldera, the world’s largest volcano, to the effects of Glacial Lake Missoula, Montana is littered with world-class geologic features to explore throughout the state.

The Roadside Geology series originated in 1972 with “Roadside Geology of the Northern Rockies.” Fourteen years later, the first edition of “Roadside Geology of Montana” was released by authors Don Hyndman and Dave Alt. Montana was the first state book in the Roadside Series. Now, nearly every state and one Canadian province have a book. Hyndman is a recently retired Professor of Geology at the University of Montana and taught Thomas when he earned his master’s degree in the late ’80s. Hyndman approached Thomas about being a co-author for the much needed updated second edition.

“It was a great honor to be asked to be the co-author of this book, especially given the high profile of the book with the general public, and the fact that I was replacing Dave Alt, one of the most well-known geologists in the profession in Montana,” Thomas said.

Thomas has been working on the publication for five years, traveling to almost every corner of the state gathering data, taking photos, and creating many of the illustrations that are used throughout the book. Thomas’s focus was on his backyard of southwest Montana, but he has traveled from the Yaak in the northwest to Alzada in the southeast, filling in new road guides and any other gaps in the book. Thomas says that even though it is technically a second edition, everything is new, and is an entirely different book.

In an article featured in the Missoulian newspaper, Thomas explained, “one of the biggest changes from the first edition of “Roadside Geology” and the present book has been the understanding of plate tectonics — how continental masses move around and shape one another. The theory was in its infancy in the 1960s when Hyndman and Alt were gathering their first inferences of geological structures in Montana. A generation later, it has become the foundation of geology studies for its ability to explain how structures that develop in one fashion get radically altered by crashing into some other structure.”

Thomas has used the first edition of the Montana book for many years in his introductory geology class, along with another book of his “Roadside Geology of Yellowstone Country,” which he has used for upper-level courses centered around Yellowstone. Both books are utilized for many summer geology camps in the Dillon area, and the updated Montana book will be of great value in future camps. 

“This is a national series, and the Montana book is the first. The ‘Roadside Geology’ idea, is one of the great public education ideas in all of geology. It is a big deal to have the Montana Western name on such a book,” Thomas said.

For more information, please contact Robert Thomas at [email protected]. To purchase a copy of the “Roadside Geology of Montana,” call The Bookstore in Dillon, Mont., at 406-683-6807 or visit