Stratigraphy and paleontology of a San Andres Formation (Permian, Leonardian) outlier, Zuni Indian Reservation, New Mexico
— Barry S. Kues and Spencer G. Lucas

4.5-m-thick sequence of massive, light gray, coarsely crystalline limestone of the San Andres Formation occurs in a limited exposure south of Ojo Caliente, near the New Mexico—Arizona border. This sequence contains fossiliferous intervals near the base and top. The lower interval contains a fauna dominated by the productoid brachiopods Peniculauris bassi and Rugatia occidentalis. The upper interval contains a bivalve-scaphopod fauna with numerous nautiloids but few gastropods and brachiopods. A conspicuous element of this fauna includes exceptionally large valves of the pectinacean bivalv  Aviculopecten? aff. A.? coreyanus. As would be expected from its location between widespread exposures of the Kaibab Formation to the west and San Andres Formation to the east, the Ojo Caliente section includes some taxa that occur in both formations. A tentative correlation of the Ojo Caliente section with the beta member (Fossil Mountain Member) of the Kaibab Formation in Arizona is supported by the presence of the brachiopods mentioned above. Subtle ecological differences in salinity, distance from shoreline and substrate probably account for the significant differences in the composition of the two Ojo Caliente assemblages.