Early career in the United States Geological Survey (USGS); Atomic Energy Commission-sponsored surveys of uranium deposits in the western United States; USGS Grand Junction, Colorado field office; nuclear explosion crater studies; the MICE project; early lunar studies sponsored by NASA. Specific topics include Shoemaker's investigations of the geology of the Colorado plateau; doctoral studies at Princeton University in the mid-1950s; his identification of coesite at the Meteor Crater, Arizona; and the Ries formation in Bavaria, Germany; the development of lunar stratigraphic principles.