Biostratigraphy of the Purgatoire Formation, West-Central Quay County, New Mexico

Exposures of units of Lower Cretaceous age in west-central Quay County, New Mexico, were studied in an attempt to establish a correlation with the Cretaceous of Texas.

The foraminiferal fauna consists of 9 families, 2B genera, and 56 species. The ostracode fauna consists of 3 families, 8 genera, and 31 species. Elements of both faunas exhibits a comparatively long stratigraphic range.

No paleontological evidence was found for the presence of Upper Washita formations. Formations of the Fredericksburg Group occur in only two sections.

The types of sediments and the contained fossils indicate two ecologically different environments of deposition in the lower member of the formation studied. The earlier environment was one of stagnation or restriction and the later environment was normal marine.