[1]The specific area about which the early-day Indians first used the term that is now translated as “Yellowstone” is unknown. The name may have referred to the yellowish rocks that line the banks of the Yellowstone River near its confluence with the Missouri River in eastern Montana and western North Dakota. However, in the opinion of H. M. Chittenden, who studied the question in considerable detail, there is little doubt that the name was taken from the striking yellow-hued walls of the gorge now known as the Grand Canyon of the Yellowstone. _Selected Additional Reading_ Allen, E. T., and Day, A. L., 1935, Hot springs of the Yellowstone National Park: Carnegie Institution of Washington Publication 466, 525 pages. Boyd, F. R., 1961, Welded tuffs and flows in the rhyolite plateau of Yellowstone Park, Wyoming: Geological Society of America Bulletin, volume 72, number 3, pages 387-426. Christiansen, R. L., and Blank, H. R., Jr., 1972, Volcanic stratigraphy of the Quaternary rhyolite plateau in Yellowstone National Park: U.S. Geological Survey, Professional Paper 729-B (in press). Dorf, Erling, 1960, Tertiary fossil forests of Yellowstone National Park, Wyoming, _in_ West Yellowstone—Earthquake area, Billings Geological Society Guidebook 11th Annual Field Conference, 1960: pages 253-260. Hague, Arnold, Iddings, J. P., Weed, W. H., Walcott, C. D., Girty, G. H., Stanton, T. W., and Knowlton, F. H., 1899, Geology of the Yellowstone National Park: U.S. Geological Survey Monograph 32, part 2, 893 pages and atlas of 27 sheets folio. Hague, Arnold, Weed, W. H., and Iddings, J. P., 1896, Description of the Yellowstone National Park quadrangle [Wyoming]: U.S. Geological Survey Geologic Atlas, Folio 30. Hayden, F. V., 1872, Preliminary report of the United States Geological Survey of Montana and portions of adjacent Territories, being a fifth annual report of progress—Part I: Washington, U.S. Government Printing Office, pages 13-204. Howard, A. D., 1937, History of the Grand Canyon of the Yellowstone: Geological Society of America Special Paper 6, 159 pages. Marler, G. D., 1969, The story of Old Faithful: Yellowstone Library and Museum Association, 49 pages. Richmond, G. M., Pierce, K. L., and Waldrop, H. A., 1972, Surficial geologic map of Yellowstone National Park: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-710 (in press). Ruppel, E. T., 1972, Geology of pre-Tertiary rocks in the northern part of Yellowstone National Park, Wyoming: U.S. Geological Survey Professional Paper 729-A (in press). Smedes, H. W., and Prostka, H. J., 1972, Absaroka Volcanic Supergroup in the Yellowstone National Park region: U.S. Geological Survey Professional Paper 729-C (in press). Smith, R. L., 1960, Ash flows: Geological Society of America Bulletin, volume 71, number 6, pages 795-841.