The red upper unit of the Hickory Sandstone is a hematitic and goethitic sandstone containing a large reserve of potential low-grade iron ore.
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.
Studies along the southern and southeastern borders of the High Plains have demonstrated the presence of outliers of fossiliferous Ogallala Formation in Borden and Scurry counties and have documented the occurrence of Pliocene deposition as far southeast as Sterling County.
Texas has a great variety of rocks and minerals some are common and others are not. This book is designed to aquaint you with some of them and to tell you in a nontechnical way what they are like, some of the places where they are found, and how they are used.