| State | Texas |
|---|---|
| Name | San Miguel Formation |
| Geologic age | Late Cretaceous; Gulfian Series |
| Lithologic constituents |
Major
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Carbonate > Limestone (Bed)
Unconsolidated > Fine-detrital > Clay (Bed)
|
| Comments | Sandstone, limestone, and clay; fossilif. sand, sandy ls., and unfossilif. clay superficially like the underlying Upson, clay increases in amount upward; fossils include Exogyra ponderosa and many other marine megafossils; thickness about 400 ft in Crystal City-Eagle Pass area, 800 ft in Del Rio area. |
| 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, 1977, Del Rio 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 | Kinney - Maverick |