The Ellenburger of Texas was first defined as a marine limestone formation of Cambrian and Ordovician age (Paige, 1912), but recently it has been subdivided into several formations and the term Ellenburger given group status (Cloud and Barnes, 1948). The group forms an important unit in the geology of Texas, its known extent in both surface and subsurface covering approximately one-half of the State (fig. 1). Consequently the Ellenburger has received the attention of many geologists over a period of more than forty years.