Shafter Formation

Shafter Formation
State Texas
Name Shafter Formation
Geologic age Early Cretaceous
Lithologic constituents
Major
Sedimentary > Carbonate > Limestone (Bed)
Minor
Sedimentary > Clastic > Mixed-clastic > Sandstone-mudstone (Bed)
Comments limestone, sandstone, shale, and marl. ls nodular to regular beds, alternating hard and marly units form a series of cuestas; ss in basal 50 ft, near middle of fm. fine to med. grained, crossbedded; fossils include Exogyra texana in upper 165 ft. thickness of formation 900 ft. crops out in Chinati Peak quadrangle and Presidio area.
References

Bureau of Economic Geology, 1979, Emory Peak--Presidio Sheet, Geologic Atlas of Texas, University of Texas at Austin.

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.

NGMDB product
Counties Presidio