Pennsylvanian stratigraphy and paleontology of the Taos area, north-central New Mexico
— Barry S. Kues

The most extensively exposed sequence of Pennsylvanian strata in New Mexico occurs in the Sangre de Cristo Mountains, where it reaches a thickness of more than 2,000 m and includes sediments deposited from earliest (Morrowan) to latest (Virgilian) Pennsylvanian time. Outcrops of Pennsylvanian age extend continuously from near Pecos and Bernal in the south to near Eagle Nest and Elizabethtown in the north, a distance of about 135 km (Fig. 1). A large variety of depositional environments is present in this sequence, including basinal terrigenous mudstones, offshore marine shelf carbonates, deltaic marine and fluvial shales, sandstones and conglomerates, and arkosic continental elastic sediments, among others. Some of the marine units are highly fossiliferous, but with the notable exception of the brachiopods, these faunas have not been comprehensively studied. This paper summarizes the Pennsylvanian stratigraphy and paleontology of the Taos area, presents preliminary observations on a remarkably diverse Middle Pennsylvanian mollusc-dominated marine fauna currently under study by the author, and includes illustrations of some of the more conspicuous molluscan species present in this fauna. All specimens illustrated in this paper are in the University of New Mexico Department of Geology paleontological collections and bear UNM catalogue numbers.