Summary of Classification of the Pennsylvanian Formations of Texas, with Special Reference to the Lower Pennsylvanian of the Llano Region

Middle and Upper Pennsylvanian beds of Texas are well known and are subdivided into a series of formations on the basis of lithology and fossils. The Lower Pennsylvanian, however, which outcrops in central Texas is more complex. Recent field work has distinguished three formations, one of which is subdivided into four members. These are briefly described and lists of characteristic fossils are presented.