Geologic map of the Mystic Lake Quadrangle, Montana
A.W. Roberts 1964 U.S. Geological Survey, Miscellaneous Geologic Investigations, Map I-398 Map I-398
This 7 1/2-minute quadrangle is dominated by Ordovician through Cretaceous sedimentary rocks overlying Precambrian gneisses. The sedimentary rocks exhibit plunging folds of various wavelengths and are cut by both a thrust fault and a high-angle fault. Robert Burger writes: 'I find students have a much easier time of working with the map if I scan the line of section at 300 dpi and at an enlargement of 200%. The scanned images are then printed on a color laser printer and assembled by students. This is the second major cross-section assigned in my course. Difficulty level for map interpretation: moderate; difficulty level for student-constructed cross sections: moderate to somewhat difficult.'