Roadside Geology of MontanaThe Roadside Geology series originated in 1972 with Roadside Geology of the Northern Rockies. Fourteen years later, the Big Sky portion of that book was updated to become Roadside Geology of Montana, a bright yellow field guide that soon graced bookshelves across the state. Now, nearly 50 years after the first book, Mountain Press is releasing this completely revised full color second edition that, like so many things in Montana, is big. But consider