[4] The formation is only sparsely fossiliferous, but contains fossils of echinoderms, gastropods, trilobites, sponge spicules, and Nuia.

Bioherms up to 6 meters (20 ft) high are found in the McKelligon Member, built up of siliceous sponges and receptaculitid Calathium.

[7] The formation was first named by George Burr Richardson in 1904 for exposures in the Franklin and Hueco Mountains.

[1] Richardson later (1908) mapped the formation into the Permian Basin and assigned the upper Ordovician beds to the Montoya Limestone.

[8] Clemons (1991) divided the formation differently, into the Hitt Canyon, Jose, McKelligon, and Padre Members.