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Buda Limestone and Del Rio Clay, undivided

Buda Limestone and Del Rio Clay, undivided
State Texas
Name Buda Limestone and Del Rio Clay, undivided
Geologic age Phanerozoic | Mesozoic | Cretaceous-Late
Comments In Eastern part of Trans-Pecos and High Plains-Buda Ls--Limestone, fine grained, bioclastic, commonly glauconitic, pyrite, hard, massive lt gray to pale orange; formation is as much as 45 ft thick. Del Rio Clay--Clay, calcar. to gypsiferous, pyrite common, blocky, med gray, weathers lt gray to lt yell-gray, contains lenses of calcar siltst., marine megafossils include abdt Exogyra arietina and other pelecypods; thickness 40-70 ft. In Western part of Trans-Pecos Texas- Buda Ls--upper part-- thin to thick beds, resistant, few chert nodules; middle--interbedded gray ls, marl, and calc shale, limonite nodules; lower--fossilif., aphanitic ls, thin to thick beds; formation is 200-350 ft thick. Del Rio Clay--lt gray to lt yell-gray marl interbedded with clayey lt gray, nodular ls. thickness 87 ft.
Primary rock type limestone
Secondary rock type mudstone
Other rock types clay or mud; siltstone; shale
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)
Minor
Sedimentary > Carbonate > Marlstone (Bed)
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Incidental
Sedimentary > Clastic > Siltstone (Bed)
Sedimentary > Clastic > Mudstone > Shale (Estuarine)
Map references
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
Unit references
Bureau of Economic Geology, 1974, San Antonio Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.
Bureau of Economic Geology, 1974, Austin Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, 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, 1981, Llano sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.
Counties Bell - Bexar - Brewster - Comal - Edwards - Hays - Hudspeth - Kerr - Kimble - Medina - Presidio - Real - Sutton - Terrell - Uvalde - Val Verde - Williamson