2026 marks 100 years of National Park Service Interpretation at Grand Canyon National Park. In honor of this anniversary, here's Louis Schellbach's introductory geology talk. Throughout his talk, he references geologic details once viewed through a series of mounted binoculars on the parapet at Yavapai Observation Station (now Yavapai Geology Museum). Schellbach served as the park's Chief Naturalist from 1941–1957.