Abstract

Upper Carboniferous and Lower Permian fusulinacean zonation is well known in west Texas, northcentral Texas and eastern Kansas. The Virgilian Series (latest Carboniferous) in the midcontinent and southwestern United States has fusulinacean zones that are generally dominated by large Triticites commonly associated with Schubertella and Dunbarinella and large specimens of Waeringella and Pseudofusulinella.

The Early Permian (Wolfcampian Series) of the midcontinent and southwestern United States has three fusulinacean zones and each is marked bv increasing diversity westward. The earliest zone contains Triticites (Leptotriticites), Triticites (Triticites), Pseudofusulina (Schwagerina of authors), Schubertella, Oketaella and sparsely distributed Pseudofusulinella. The middle fusulinacean zone includes the successive introduction of Paraschwagerina, Pseudoschwagerina, Schwagerina, Stewartina, and Eoparafusulina. The highest Wolfcampian fusulinacean zone includes most genera (except Triticites) of the earlier two zones plus the introduction of Chalaroschwagerina.

In the Glass Mountains the earliest of these three zones is apparently missing (unless it is present but not recognized in Bed 2 of King’s Gray Limestone). The middle zone is present in the Neal Ranch Formation and the upper zone is present in the Lenox Hills Formation. Unconformities in the upper part of the Gaptank Formation, at the base of the Neal Ranch, the Lenox Hills and the Skinner Ranch Formations suggest that the depositional record has several stratigraphic breaks.