[23]Pipiringos and O’Sullivan, 1975.
[24]According to Fred Peterson, U.S. Geological Survey.
[25]Wright, Shawe, and Lohman, 1962; [Lohman, 1975].
[26]Paul L. Williams, U.S. Geological Survey, told me in November 1978 that he observed H₂S-bearing spring water leaching the color from both the Entrada and Wingate Sandstones above Tabeguache Creek some 8 or 10 miles north of Nucla, Colo., and from the Wingate alone along Onion Creek in eastern Utah.
[27]Lohman, 1965a, p. 47, 48.
[28]Study of a fauna of small vertebrates from the late Jurassic Morrison Formation of western Colorado, by George C. Callison, 21 pages, June 1978.
[29]A, modified from Gilmore, courtesy U.S. National Museum; B, modified from Gilmore, courtesy Carnegie Museum; C, modified from Mathew, courtesy American Museum of Natural History; and D, modified from Romer, after Marsh and Gilmore, courtesy University of Chicago Press.
[30]From information obtained in several discussions with John R. Donnell. U.S. Geological Survey.
[31]See Cater, 1970, p. 67.
[32]Lohman 1961, 1965a, 1965b; Hunt 1969, p. 87.