|Geologic age||Late Cretaceous|
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Bed)
Sedimentary > Clastic > Mixed-clastic > Siltstone-mudstone (Bed)
Sedimentary > Carbonate > Marlstone (Bed)
|Comments||In Western part of Trans-Pecos Texas, Eastern part of Trans-Pecos Texas and High Plains- limestone, marl and shale. Upper part--interbedded marl and shale; lower part--limestone, silty to sandy, flaggy, dark grayish orange near base; marine megafossils; thickness 200+_ ft. In North, central, and south Texas including Quaternary for all of west Texas- Four units. Upper unit mostly silty shale, med-gray interbedded with nodular to laminar ls. Followed downward by shale, silty interbedded with granular yell-gray ls.; shale silty dk-gray interbedded with laminated siltstone; a basal unit of limest. clastic in thin mostly cross-laminated beds, interbedded with siltstone. Thickness 160-220 ft.|
Bureau of Economic Geology, 1968, Van Horn-El Paso Sheet, Geologic Atlas of Texas: Bureau of Economic Geology, The University of Texas at Austin, scale 1:250,000.
Bureau of Economic Geology, 1977, Del Rio Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.
Bureau of Economic Geology, 1992, Geologic Map of Texas: University of Texas at Austin, Virgil E. Barnes, project supervisor, Hartmann, B.M. and Scranton, D.F., cartography, scale 1:500,000.
|Counties||Brewster - Crockett - Culberson - Edwards - Jeff Davis - Pecos - Presidio - Reeves - Sutton - Terrell - Val Verde|