Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided (TXOCA;0)

State	Texas
Name	Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided
Geologic age	Cambrian and Ordovician
Lithologic constituents	Major Sedimentary > Carbonate > Limestone (Bed) Minor Sedimentary > Clastic > Sandstone (Bed) Incidental Sedimentary > Chemical > Chert (Bed) Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)
Comments	Units, from top to bottom (fr. Fort Stockton Sheet, Geologic Atlas of Texas): Woods Hollow Shale-greenish clay shale with interbedded laminated gray to yellowish sandy limestone and limy sandstone; some beds of coarsely granular conglomeratic limestone crowded with fragmental fossils; thickness 300-400 ft. Fort Pena Formation- alternations of thick bedded ls. in part sandy, with bedded bluish and purplish chert; some thin shale partings; near base one or more beds of cs. conglo; thickness 125-200 ft Alsate Shale- hard green shale; thin ls. beds common; conglo. locally at base, thickness of unit 24-145 ft Marathon Limestone, flaggy dk-gray to gray-black ls., weathers ashen gray, with shale intervals and partings, intraformational conglo., and some sandst. beds; near middle Monument Spring Dolomite Member, up to 94 ft thick; thickness of fm.350-1000 ft. Dagger Flat Sandstone-medium grained, massive saccharoidal ss. with interbedded shale, some calcareous beds in upper part; brownish yellow to yellowish brown, weathers light brown; exposed near the axes of anticlinoria 5-7 mi SE of, 11 mi S. of Marathon and near Dagger Flat, Brewster Co., thickness about 300 ft, base not exposed.
References	Bureau of Economic Geology, 1982, Fort Stockton Sheet, Geologic Atlas of Texas, 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	NGMDB product page for 68390
Counties	Brewster - Jeff Davis - Presidio

State

Texas

Name

Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided

Geologic age

Cambrian and Ordovician

Lithologic constituents

Major

Sedimentary > Carbonate > Limestone (Bed)

Minor

Sedimentary > Clastic > Sandstone (Bed)

Incidental

Sedimentary > Chemical > Chert (Bed)

Sedimentary > Clastic > Mudstone > Shale > Black-shale (Bed)

Comments

Units, from top to bottom (fr. Fort Stockton Sheet, Geologic Atlas of Texas): Woods Hollow Shale-greenish clay shale with interbedded laminated gray to yellowish sandy limestone and limy sandstone; some beds of coarsely granular conglomeratic limestone crowded with fragmental fossils; thickness 300-400 ft. Fort Pena Formation- alternations of thick bedded ls. in part sandy, with bedded bluish and purplish chert; some thin shale partings; near base one or more beds of cs. conglo; thickness 125-200 ft Alsate Shale- hard green shale; thin ls. beds common; conglo. locally at base, thickness of unit 24-145 ft Marathon Limestone, flaggy dk-gray to gray-black ls., weathers ashen gray, with shale intervals and partings, intraformational conglo., and some sandst. beds; near middle Monument Spring Dolomite Member, up to 94 ft thick; thickness of fm.350-1000 ft. Dagger Flat Sandstone-medium grained, massive saccharoidal ss. with interbedded shale, some calcareous beds in upper part; brownish yellow to yellowish brown, weathers light brown; exposed near the axes of anticlinoria 5-7 mi SE of, 11 mi S. of Marathon and near Dagger Flat, Brewster Co., thickness about 300 ft, base not exposed.

References

Bureau of Economic Geology, 1982, Fort Stockton Sheet, Geologic Atlas of Texas, 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

NGMDB product page for 68390

Counties

Brewster - Jeff Davis - Presidio