Twin Mountains Formation (TXKtm;0)

State	Texas
Name	Twin Mountains Formation
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Early
Original map label	Ktm
Comments	Upper part mostly sandst., some clayst. and conglomerate. Middle part sandstone above claystone. Lower part mostly sandst., some clayst. and conglomerate. Thickness about 150 ft.
Primary rock type	sandstone
Secondary rock type	claystone
Other rock types	conglomerate
Lithologic constituents	Major Sedimentary > Clastic > Sandstone (Bed) Sedimentary > Clastic > Mudstone > Claystone (Bed) Incidental Sedimentary > Clastic > Conglomerate (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, 1972, Dallas sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, scale 1:250,000. Bureau of Economic Geology, 1967, Sherman Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
Geographic coverage	Brown - Comanche - Eastland - Erath - Hamilton - Hood - Jack - Palo Pinto - Parker - Somervell - Wise