Geological Survey Bulletin 1271—E Pecos National Monument New Mexico: Its Geologic Setting

Abert, J. W., 1848, Report on examination of New Mexico in the years 1846-47: Rept. Secretary War, U.S. 30th Cong., 1st sess., S. Ex. Doc. 23, p. 3-130; H. Ex. Doc. 41, p. 417-546.

Gregg, Josiah, 1844, Commerce of the prairies [Moorhead, Max, ed., 1954]: Norman, Oklahoma Univ. Press, p. 469.