The Cathedral Mountain Formation is a geologic formation in Texas that preserves fossils from the Permian period. In the Glass Mountains of West Texas, its rock layers form part of the region’s stratigraphy and help document ancient environments and life from hundreds of millions of years ago. It has appeared in geological research on the Glass Mountains since at least the early 20th century, including work by Philip Burke King and later researchers. Its chief significance today lies as a fossil-bearing rock unit within Texas geology and as part of the evidence used to understand Permian paleontology in the region.