was first defined by V.C. Kelley in 1977 for beds formerly assigned to the upper buff member of the Santa Fe Formation (now the Santa Fe Group) by Kirk Bryan and Franklin T. McCann in 1936. S.D. Connell and coinvestigators reassigned the member to the Arroyo Ojito Formation in 1999. In 2007, Williams and Cole recommended that the Arroyo Ojito Formation be abandoned, because the name was being used inconsistently and because the formation straddled a significant regional unconformity since named the Rincones paleosurface. They raised the Ceja Member, which lay above the Rincones paleosurface, to formation rank, a recommendation with which Connell subsequently concurred. See also List of fossiliferous stratigraphic units in New Mexico Paleontology in New Mexico References Bibliography Neogene formations of New Mexico Pliocene Series of North America Piacenzian Zanclean Messinian Tortonian Sandstone formations of the United States Fluvial deposits