Cox Sandstone (TXKcx;0)

State	Texas
Name	Cox Sandstone
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Early
Original map label	Kcx
Comments	Interbedded nodular limestone and ferruginous sandstone at north end of Chinati Mtns. Also minor shale and marl there. Upper part about one-third limestone, thin-bedded, hard, nodular, rest mostly shale, gray, red, and interbeds of marl and sandstone, abundant Exogyra texana. Lower part sandstone, fine to med grained, resistant, thick beds, crossbedded; few thin beds of fossilif. limest. toward base, grades downward to Bluff Mesa Fm. Thickness 450 ft; Amsbury (1958) measured about 500 ft in Pinto Canyon, Chinati Mtns, Presidio Co.
Primary rock type	mixed clastic/carbonate
Secondary rock type	limestone
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Mixed-clastic > Sandstone-Mudstone (Bed) Minor Sedimentary > Carbonate > Limestone (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, 1979, Emory Peak--Presidio Sheet, Geologic Atlas of Texas, University of Texas at Austin. Bureau of Economic Geology, 1968, Van Horn-El Paso Sheet, Geologic Atlas of Texas: Bureau of Economic Geology, The University of Texas at Austin, scale 1:250,000.
Geographic coverage	Culberson - Hudspeth - Jeff Davis - Presidio - Reeves