Walcott became Director of the U.S. Geological Survey 1894–1907, and Secretary of the Smithsonian Institution, 1907–1927. He discovered a number of important fossil sites. At the Walcott Quarry, the lowest (earliest) of the Burgess Shale deposits, Walcott collected 65,000 specimens between 1910 and 1924. The site dates to the Middle Cambrian, and is in the Canadian Rockies.