|Paluxy Sandstone, East Texas Basin
According to Owen's (1979) outcrop study of the Paluxy sand in north central Texas, the Paluxy is a quartzarenite consisting of medium to very fine quartz sand and coarse silt, with variable amounts of limonite, hematite, pyrite, and magnetite and insignificant amounts of tourmaline and feldspar. The Paluxy also contains significant amounts (as much as 50 percent in Hood, Parker, and Tarrant Counties) of clay. In general the clay fraction consists of 40 to 50 percent quartz, 5 to 25 percent feldspar, 30 to 40 percent montmorillonite, and less than 10 percent illite and kaolinite. Most of the quartz is of plutonic origin, with lesser amounts of volcanic and vein quartz.
Owen, M. T., 1979, The Paluxy sand in north central Texas: Baylor Geological Studies, Bulletin No. 36, 36 p.