Marli B. Miller is a senior instructor and researcher at the University of Oregon. She completed her BA in geology at Colorado College in 1982 and her MS and PhD in structural geology at the University of Washington in 1987 and 1992, respectively, where coauthor Darrel Cowan was her thesis advisor. Marli teaches a variety of courses, including introductory geology, structural geology, field geology, and geophotography. In addition to numerous technical papers, she is the author of Roadside Geology of Oregon and coauthor of Geology of Death Valley National Park. She is the photographer for What�s So Great About Granite, written by Jennifer Carey, the editor of this Roadside Geology book! Marli has two daughters, Lindsay and Megan. Darrel S. Cowan received his BS and PhD in geology from Stanford University and served as an exploration geologist in the Alaska Division of Shell Oil Company from 1971 until 1974. He accepted a faculty position at the University of Washington in Seattle in 1974 and currently teaches in the Department of Earth and Space Sciences. Darrel�s research interests include processes at ancient subduction zones and the late Mesozoic tectonic evolution of the western margin of North America. Although his field research has taken him and his students all over the world, the San Juan Islands in Washington rank high on his list of geologic puzzles worthy of study. In 2014, Darrel received the Career Contribution Award from the Division of Structural Geology and Tectonics of the Geological Society of America.