Cedarton Shale and Adams Branch Limestone, undivided

Cedarton Shale and Adams Branch Limestone, undivided
State Texas
Name Cedarton Shale and Adams Branch Limestone, undivided
Geologic age Pennsylvanian; Missouri Series
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Minor
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Sandstone (Bed)
Comments (fr. Brownwood Sheet, 1976) Cedarton Shale--shale, mudst., ls., and sandst. Mostly shale, silty, local lenses of dk gray bioclastic argillaceous ls., lenses of mudst., a few thin sporadic lenses of thin bedded, med-grained laminated sandst., locally rich in pelecypods and gastropods, some unmapped ss south of Colorado River, shale mostly gray, mottled red upward, locally fossiliferous, contains brachiopods, crinoid columnals, echinoderm frags, pelecypods, impressions of leaves, and chips of carbonized wood. equiv. to upper part of Wolf Mtn Shale in Brazos River valley of Abilene Sheet. Sandstone v fine grained to coarse grained, local conglomerate, thin to thick beds, gray, weathers red to brn, north body, as much as 80 ft thick, cuts into Adams Branch Ls. south body 15 to 30 ft thick. total thickness of Cedarton Sh 15 to 50 ft , max 80 ft locally. Adams Branch Limestone-- ls, pelleted, plasticlasts in 30-ft interval near top to south of Colorado River. Clayey tongues at base near Brownwood, grades north into clayey ls interbedded with shale, siltstone, and sandst., passes into sandst. at Cretaceous overlap, discontinuous east and SE of Rochelle, calcified SW of Rochelle, thin beds and massive wavy beds, v. lt. gray to med. gray, locally cut out by sandst., forms scarp with braod dip slope north of Colorada River. Quarried at Brownwood. Contains fusulinids, algae, brachiopods, and crinoid frags. Prob. equi. to Staff Ls. in Brazos River valley. Thickness averages 15 to 20 ft.
Stratigraphic units Canyon Group
References

Bureau of Economic Geology, 1976, Brownwood sheet, Geologic Atlas of Texas, Bureau of Economic Geology, University of Texas at Austin, 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 Brown - McCulloch