Grayson Marl and Main Street Limestone, undivided (TXKgm;0)

State	Texas
Name	Grayson Marl and Main Street Limestone, undivided
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Early Cretaceous-Late
Original map label	Kgm
Comments	Grayson Marl mostly marl, lt greenish-gray to med. gray, near top some thin interbeds of limest., nodular, sl. sandy, gray, fossiliferous; weathers grayish-yellow; thickness 15-60 ft. Main Street Limestone, thick ls beds, coarse grained, hard, interbedded with thin marl beds; yell-gray, white, brown; thikcness 10-20 ft.
Primary rock type	mudstone
Secondary rock type	limestone
Other rock types
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Estuarine) Sedimentary > Carbonate > Marlstone (Estuarine)
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, 1967, Sherman Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
Geographic coverage	Bell - Bosque - Cooke - Coryell - Denton - Grayson - Hill - Johnson - McLennan - Tarrant