The Geology of the Palmer Quadrangle, Ellis County, Texas

Location of Palmer Quadrangle.-This quadrangle lies in northeastern Ellis County. It is bounded by the meridians 96° 37\u27 30 and 96° 45\u27 00 , and by the parallels 32° 22\u27 30 and 32° 30\u27 00 , and includes an area of some 61 square miles. U.S. Highway 75 crosses the quadrangle, and there is a complementary network of secondary roads. Palmer, Trumbull, and Boyce are the only towns within the area. General Stratigraphy.-Bedrock consists of the upper chalk member of the Austin chalk and two members of the Taylor marl, the Lower Taylor marl member and the Wolfe City sandstone member. All units are of Upper Cretaceous age. Quaternary terrace deposits cover most of the bedrock surface. Recent alluvium is found on stream floodplains. Physiographic Setting.-The Palmer Quadrangle lies on the northwestern margin of the Gulf Coastal Plain. It is characterized by the level plains, low-rolling hills, and low-gradient streams found throughout this physiographic province. Noticeable throughout most of the quadrangle are the broad, flat interstream plains, mantled by Quaternary terrace deposits. To the south most of the terrace material has been eroded off, leaving the gently-rolling hills of the Taylor marl. In the southeast part of the quadrangle, east of Grove Creek, the Wolfe City sandstone member forms a low but distinct cuesta since the sandstone is more resistant to erosion than the underlying marl. Most of the quadrangle is drained by the east flowing intermittent tributaries of the Trinity River, Red Oak and Grove Creeks. Purpose and Method of Study.-The study of this area is a portion of a regional mapping program in north central Texas by the Department of Geology of Southern Methodist University. The principal contribution of the study is the geologic map. Field work was done in the spring and summer of 1957. Areal geology was plotted directly on aerial photographs and then transferred to a controlled mosaic with a scale of one inch to one thousand feet. A tracing of the mosaic was then reduced to provide the final geologic map, on the scale of about two inches to the mile