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Wellborn Formation

Wellborn Formation
State Texas
Name Wellborn Formation
Geologic age Phanerozoic | Cenozoic | Tertiary | Eocene
Comments In north, central, and south Texas including Quaternary for all of west Texas- Sandstone, fine to coarse grained, lt gray, crossbedded, contains borings of worms and Ophiomorpha burrows and fossil shells; locally well indurated; thickness about 150 ft. In East Texas and Gulf Coast to Rio Grande- quartz sand, v. fine to fine grained, sl. glauconitic, increasingly glauconitic eastward (in Palestine Sheet (1968), interbeds of brown lignitic clay and lignite; lt. brown, weathers dk gray; marine megafossils locally; thickness 50 ft, feathers out eastward
Primary rock type sandstone
Secondary rock type sand
Other rock types clay or mud; coal
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Glauconitic)
Incidental
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Sedimentary > Coal > Lignite (Bed)
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, 1976, Crystal City-Eagle Pass Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.
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, Seguin Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.
Bureau of Economic Geology, 1967, Palestine Sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000.
Counties Angelina - Atascosa - Brazos - Burleson - Fayette - Gonzales - Grimes - Houston - Karnes - Lee - McMullen - Madison - Polk - Trinity - Walker - Wilson