Stratigraphic range: Early Cretaceous, 112 Ma
The Purgatoire Formation is an abandoned (1987) Cretaceous period geologic formation classification. The classification was used in Colorado, New Mexico, and Oklahoma, with mentions in older geologic literature in neighboring states.
Units previously classified as members of the abandoned formation, including Lytle, Mesa Rica, Pajarito, Romeroville, and Glencairn, have been generally elevated to formation rank. Particularly, significant divisions of the Purgatoire classification, Lytle and Glencairn, were realized as having characteristics of formations in their own right as well as representing the greatest disconformity in the Lower Cretaceous sediments of the Western Interior Seaway. Rather than including these promoted formations in an elevated Purgatoire Group, the Mesa Rica, Pajarito, and Romeroville were placed in a definition of the Dakota Group local to the Dry Cimarron.
- Atkinson, L. "THEIOPHYTALIA :: from DinoChecker's dinosaur archive". ‹http://www.dinochecker.com/dinosaurs/THEIOPHYTALIA›. Web access: 13th Sep 2020.
- "Geologic Unit: Purgatoire". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2021-03-24.
Use of Purgatoire formation in Tucumcari-Sabinoso area, Guadalupe, Harding, San Miguel, and Quay Cos, northeast NM in the Palo Duro basin and on the Sierra Grande uplift abandoned [should read "areally restricted"].
Term Purgatoire abandoned. Both Lytle and Glencairn are mappable at 1:24,000, and they are separated by a disconformity--the most significant break in the Lower Cretaceous. Authors believe there is no reason to retain them as member rank or to raise the Purgatoire to group rank.
- "Geologic Unit: Dakota". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2021-03-24.
- Griggs and Read, 1959.