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Calvert Bluff Formation

Calvert Bluff Formation
State Texas
Name Calvert Bluff Formation
Geologic age Phanerozoic | Cenozoic | Tertiary | Paleocene Eocene
Comments Mostly mudstone with varing amounts of sandstone, lignite, ironstone concretions, and in uppermost part locally glauconitic. Mudst. massive to thinn bedded weathers yell-brn. Sandst. med to fine grained, mod. well sorted, crossbedded, lenticular. Lignite mostly in lower part of formation, seams 1-20 ft thick, brownish black. thickness about 1,000 ft.
Primary rock type mudstone
Secondary rock type sandstone
Other rock types coal
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Claystone (Bed)
Minor
Sedimentary > Clastic > Sandstone (Bed)
Incidental
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, 1974, Austin Sheet, Geologic Atlas of Texas, University of Texas, Bureau of Economic Geology, scale 1:250,000.
Counties Bastrop - Burleson - Falls - Freestone - Leon - Limestone - Robertson