TY - RPRT TI - Nineteenth Annual Report of the United States Geological Survey to the Secretary of the Interior 1897 - 1898: Part II - Papers Chiefly of a Theoretic Nature AU - Charles D. Walcott PY - 1899 DO - 10.3133/ar19_2 UR - https://pubs.usgs.gov/publication/ar19_2 ID - ar19_2 ER -