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The Triassic System in the Zuni Mountains consists of one Middle Triassic unit, the Moenkopi Formation, the Upper Triassic Chinle Group, and the Upper Triassic-Lower Jurassic (?) Wingate Sandstone. The Chinle Group in the Zuni Mountains consists of six formations, in ascending order: Zuni Mountains (named here;=“mottled strata” of previous workers), Shinarump, Bluewater Creek, Petrified Forest, Owl Rock, and Wingate formations. The Moenkopi Formation rests on an unconformable surface that represents the compound Tr-0 through Tr-2 unconformities, and Moenkopi strata locally rest on either the San Andres or Glorieta formations, both of Early Permian age. Moenkopi strata in the Zuni Mountains are relatively thin (< 25 m thick) sequences of thinly bedded sandstone, siltstone, and conglomerate, overlain by the Zuni Mountains and/or Shinarump formations, which lie on a surface corresponding to the Tr-3 unconformity. The Moenkopi Formation in the Zuni Mountains is lithologically identical to the Anton Chico Member of the Moenkopi Formation in eastern New Mexico, and is presumably correlative to both that unit and the Holbrook Member in western Arizona, and is thus of Perovkan (early Anisian) age. We coin the term Zuni Mountains Formation to replace the long-used informal term “mottled strata.” Zuni Mountains Formation strata are color-mottled siliciclastics that record pedogenic modification of strata associated with development of the Tr-3 unconformity. Shinarump Formation strata are principally conglomerates and sandstone that represent channel deposits of a fluvial system that aggraded in Tr-3 paleotopography during early …