This report is a compilation of all available data on mineral resources (exclusive of oil and gas) in 39 south Texas counties. Information from published and unpublished sources was checked and supplemented by field investigations.

The Pemberton Hill-Lewisville (T-2) terrace deposits of the Trinity River in Dallas and Denton Counties are divided into four consecutive members. Sixty-three vertebrates, 32 mollusks, and several insects and plants were collected from 3 members and are discussed in the report. The terrace deposits are tentatively referred to as the Sangamon interglacial on the basis of two radiocarbon dates in excess of 3700 years BP and on the association of the giant bison with a typical interglacial fauna.

The Blach Ranch and Breckenridge limestone members of the Thrifty formation are the most persistent mappable rock units in the Cisco group of the Brazos and Trinity River valleys. These limestone beds occur above the complex post-Bunger deposits of the Graham formation and below an equally complex section of Harpersville rocks.