Catahoula Formation and Frio Clay, undivided

Catahoula Formation and Frio Clay, undivided
State Texas
Name Catahoula Formation and Frio Clay, undivided
Geologic age Oligocene
Lithologic constituents
Major
Unconsolidated > Fine-detrital > Clay (Bed)
Minor
Sedimentary > Clastic > Conglomerate (Bed)
Unconsolidated > Coarse-detrital > Sand (Bed)
Incidental
Igneous > Volcanic > Mafic-volcanic > Andesite
Igneous > Volcanic > Felsic-volcanic > Trachyte
Comments Frio Clay-- clay dark greenish-gray, massive, some gypsum and calcareous concretions; thickness about 200 ft feathers out northward on Crystal City-Eagle Pass Sheet (1976). In Crystal City-Eagle Pass Sheet (1976), Catahoula Formation--upper member, Chusa Tuff Mbr is tuffaceous mudstone and sand and sandstone about 180 ft thick. next member descending is Soledad Volcanic Conglo. Mbr, abdt. pebbles, cobbles, and boulders up to one foot in size, rhyolite, trachyte, trachyandesite, thickness up to 75 ft; Fant Tuff Mbr, lowest mbr., tuff, claystone, and sandstone about 600 ft thick. Catahoula Fm. 120-300 ft thick on Seguin Sheet (1974) thins northward.
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, 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 Jim Hogg - Starr - Webb - Zapata