Restricted to geological sciences majors. Methods of geologic mapping with topographic maps and aerial photographs. Field studies include measuring sections, interpretation of stratigraphy, structure, environments of deposition of various sedimentary rocks, and the origin and petrology of igneous and metamorphic rocks. Students must register for this course during the first summer registration period. Given for six weeks each summer in Colorado, New Mexico, and other western states. Prerequisite: Geological Sciences 420K and 428 with a grade of at least C- in each.