PORVENIR FORMATION (NEW NAME) - AND OTHER REVISIONS OF NOMENCLATURE OF MISSISSIPPIAN, PENNSYLVANIAN, AND LOWER PERMIAN ROCKS, SOUTHEASTERN SANGRE DE CRISTO MOUNTAINS, NEW MEXICO.

In the Sangre de Cristo Mountains of north-central New Mexico rocks of Mississippian, Pennsylvanian, and Early Permian ages are exposed widely. The details of stratigraphy still are not known well because of the stratigraphic and structural complexity of the rocks and the rugged terrain that is poorly accessible. Therefore, the purposes of this report are to review the history of nomenclature and to specify some adjustments and revisions of stratigraphic terminology that are consistent with recent regional geologic and paleontologic findings as well as with older work. Refs.