First published use of name other than in figures or casual mention. Name attributed to Young (1966, unpub. dissert., Washington Univ., St. Louis, MO). Includes all volcanic deposits on Hualapai Plateau [for which unit was probably named] located in western Grand Canyon, Mohave Co, AZ, Plateau sedimentary province. Type not designated. Consists of andesite, basalt, tuff, cinders and fluvial volcanic-bearing sediments. Volcanics are interbedded with Buck and Doe Conglomerate, which is shown in correlation diagram (fig. 17) to underlie Hualapai. Underlies Willow Springs Formation (first used). Assigned middle Miocene age based on date on tuff of 18.3 +/-0.6 m.y. (Damon, 1964, Ann. prog. report to US Atomic Energy Comm., Geochron. Lab., Univ. AZ).

Source: GNU records (USGS DDS-6; Denver GNULEX).