The Elephant Butte Member contains silicified fossils of the demosponge Chaetetes, brachiopods, solitary corals and fusulinids.

The Whiskey Canyon Member contains crinoids, brachiopods, solitary corals, rare calcareous algae, and fusulinids.

The Garcia Member contains crinoids, brachiopods, rare bryozoans, fusulinids, calcareous algae, and oncoids.

[2] The Pennsylvanian stratigraphy of New Mexico has historically been unusually complex and inconsistent, with dozens of names for groups, formations, and members.

[5][1] Kues and Giles recommended that the name Madera Group be applied to similar exposures of shelf and marginal basin beds of Desmoinean (upper Moscovian) to early Virgilian age found from north-central and central New Mexico south along the west side of the Orogrande Basin as far as the Caballo and Robledo Mountains.