|Name||Woods Hollow Shale, Fort Pena Formation, Alsate Shale, Marathon Limestone, and Dagger Flat Sandstone, undivided|
|Geologic age||Cambrian and Ordovician|
Sedimentary > Carbonate > Limestone (Bed)
Sedimentary > Clastic > Sandstone (Bed)
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.|
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.
|Counties||Brewster - Jeff Davis - Presidio|