Biostratigraphy/ecostratigraphy of the early Pennsylvanian Osha Canyon formation at Guadalupe Box, Jemez Mountains, New Mexico
— Patrick J. Carey, Spencer G. Lucas, and Deborah Petrak Green, [eds.]

Abstract—The Osha Canyon Formation is a 27-m-thick sequence of limestone and shale of Morrowan age that is well exposed above and north of Guadalupe Box in northern New Mexico. It is richly fossiliferous, especially in its lower half, where attached brachiopods such as Schizophoria are abundant in intercalated shale and calcarenite limestone at the type section. Elsewhere in the formation are exposures where different sediment types, and therefore different environments of deposition, prevailed. These environments include low areas that accumulated micrite and an environmentally adapted, spinose productid fauna and shale-limestone cycles in which the brachiopods are silicified to a high degree. The Osha Canyon Formation preserves brachiopod-dominated fossil assemblages that mostly reflect changes in its marine ecology, expressed both stratigraphically and geographically, during part of Morrowan time.