Montana's diverse and challenging geology is evident, from its western mountains lifted and folded by tectonics and sculpted by glaciers, to its vast eastern plains partly overlain by glacial till and dissected by wind and water.
The Geologic Map of Montana includes three parts. Plate 1 is the geologic map of the state (approx. 4 x 7 ft). Plate 2 provides supporting and complementary information including the correlation chart of surface rocks with generalized lithologic information. The third part is a booklet containing all figures shown on plates 1 and 2, additional figures, the description of map units, list of source maps for plate 1, and references cited for all plates, figures, and text.