Waters from geysers, hot springs, and pools of Yellowstone National Park have been analyzed by numerous investigators extending back nearly ten decades. Large compilations of complete major ion analyses of the thermal waters have been reported by Gooch and Whitfield (1888) 38 analyses; Allen and Day (1935) 94 complete and 127 partial major ion analyses, Rowe and others (1973) 166 analyses including many previous chemical analyses of the same feature; and Thompson and others (1975) 242 complete and 299 partial major ion analyses. Smaller compilations of the thermal water chemistry have been reported by Douglass (1939) 12 analyses; White and others (1963) 6 analyses; and Scott (1964) 10 analyses. Partial chemical analyses have been reported by White and others (1956) and by Morey and others (1961) for dissolved silica; Noguichi and Nix (1963) for dissolved silica and major anions; Araki and Noguichi (1969) for dissolved silica, molybdenum, vanadium, and major anions. Here we report 422 complete major ion analyses from 330 different locations of geysers, hot springs, and pools, collected from 1974 to 1978. Many of the analyses from Upper, Midway, Lower, and Norris Geyser Basin are recollections of features previously reported.
