TY - RPRT TI - Twentieth Annual report of the United States Geological Survey, 1898-1899: Part VI (continued) - Mineral Resources of the United States, 1898, Nonmetallic Products, Except Coal and Coke AU - Charles D. Walcott PY - 1899 DO - 10.3133/ar20_6continued UR - https://pubs.usgs.gov/publication/ar20_6continued ID - ar20_6continued ER -