Marlbrook Marl (TXKmb;0)

State	Texas
Name	Marlbrook Marl
Geologic age	Phanerozoic \| Mesozoic \| Cretaceous-Late [Gulfian]
Original map label	Kmb
Comments	Clay, calcareous, variable amount of silt and glauconite, limestone bed in so. Collin Co. 10-13 inches thick, aphanitic, lt. gray, forms scarp 180 ft above base; light yell-gray, marine megafossils, thickness 300 +- ft.
Primary rock type	clay or mud
Secondary rock type	limestone
Other rock types
Lithologic constituents	Major Unconsolidated > Fine-detrital > Clay (Bed) Incidental 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, 1967, Sherman Sheet, Geologic Atlas of Texas: University of Texas at Austin, Bureau of Economic Geology, scale 1:250,000.
Geographic coverage	Bowie - Collin - Delta - Fannin - Hunt - Lamar - Red River - Rockwall