Since the days of R. T. Hill (1901) two Upper Cretaceous lithic units have been used as formations but have remained unnamed. These two units have usually been called the "Lower Taylor Marl” and the “Upper Taylor Marl.” If Taylor is used as a group, both of these formations belong in the Taylor Group.

This circular presents the history of "geological survey" in Texas from its beginning in 1858, through its intermittent early history, to [1965]. It also shows that any organization which carried the name "survey" was very short-lived in Texas. Whether this is because of early legislators’ convictions that a survey was something that was organized to do a specific job and then terminated, or whether there were deeper causes for the ephemeral nature of the early surveys is a matter for more thorough historical research and analysis.

Sediments of the Fredericksburg Division in south-central Texas were deposited on the slowly subsiding west flank of the Tyler basin. In this region there are three stratigraphically distinct areas. The southern area has a thick Edwards Limestone unit overlying a thin Walnut Formation. The intermediate area has a thinner Edwards sequence and Comanche Peak Limestone intervening between the Edwards and an expanded Walnut Formation.

The red upper unit of the Hickory Sandstone is a hematitic and goethitic sandstone containing a large reserve of potential low-grade iron ore. It is estimated that about 7 million long tons of elemental iron is locked up in each square mile of the upper 30 feet of this deposit in sandstone averaging about 12.4 percent elemental iron.