Geologic units in Carbon county, Pennsylvania

Duncannon Member of Catskill Formation (Devonian) at surface, covers 19 % of this area

Grayish-red sandstone, siltstone, and mudstone in fining-upward cycles; conglomerate occurs at base of some cycles.

Mauch Chunk Formation (Mississippian) at surface, covers 14 % of this area

Grayish-red shale, siltstone, sandstone, and some conglomerate; some local nonred zones. Includes Loyalhanna Member (crossbedded, sandy limestone) at base in south-central and southwestern Pennsylvania; also includes Greenbrier Limestone Member, and Wymps Gap and Deer Valley Limestones, which are tongues of the Greenbrier. Along Allegheny Front from Blair County to Sullivan County, Loyalhanna Member is greenish-gray, calcareous, crossbedded sandstone.

Pocono Formation (Mississippian) at surface, covers 13 % of this area

Light-gray to buff or light-olive-gray, medium-grained, crossbedded sandstone and minor siltstone; commonly conglomeratic at base and in middle; medial conglomerate, where present, is used to divide into Mount Carbon and Beckville Members; equivalent to Burgoon Sandstone of Allegheny Plateau.

Spechty Kopf Formation (Mississippian and Devonian) at surface, covers 9 % of this area

Light- to olive-gray, fine- to medium- grained, crossbedded sandstone, siltstone, and local polymictic diamictite, pebbly mudstone, and laminite; arranged in crude fining-upward cycles in some places; locally has grayish-red shale near top and conglomerate at base and in middle.

Long Run Member of Catskill Formation (Devonian) at surface, covers 6 % of this area

Gray and grayish-red sandstone and grayish-red siltstone and mudstone in fining-upward cycles.

Mahantango Formation (Devonian) at surface, covers 5 % of this area

Gray, brown, and olive shale and siltstone; marine fossils. Includes the following members, in descending order: Tully-argillaceous limestone; Sherman Ridge, Montebello (sandstone), Fisher Ridge, Dalmatia, and Turkey Ridge. In south-central Pennsylvania, includes Clearville, Frame, Chaneysville, and Gander Run Members. Characterized by coarsening-upward cycles.

Walcksville Member of Catskill Formation (Devonian) at surface, covers 5 % of this area

Greenish-gray sandstone and red siltstone and mudstone in fining-upward cycles.

Trimmers Rock Formation (Devonian) at surface, covers 3 % of this area

Olive-gray siltstone and shale, characterized by graded bedding; marine fossils; some very fine grained sandstone in northeast; black shale of Harrell Formation at base in Susquehanna Valley.

Poplar Gap Member of Catskill Formation (Devonian) at surface, covers 3 % of this area

Gray and light-olive-gray sandstone, conglomerate, and siltstone containing intermittent red beds; laterally equivalent to Clarks Ferry, Sawmill Run, and Berry Run Members.

Marcellus Formation (Devonian) at surface, covers 3 % of this area

Black shale; sparse marine fauna and siderite concretions. Contains local limestone (""Purcell"") member. Tioga bentonite included at base in eastern Pennsylvania.

Llewellyn Formation (Pennsylvanian) at surface, covers 3 % of this area

Gray, fine- to coarse-grained sandstone, siltstone, shale, conglomerate, and numerous anthracite coals in repetitive sequences.

Pottsville Formation (Pennsylvanian) at surface, covers 3 % of this area

Gray conglomerate, fine- to coarse-grained sandstone, and siltstone and shale containing minable anthracite coals. Includes three members, in descending order: Sharp Mountain--conglomerate and conglomeratic sandstone; Schuylkill--sandstone and conglomeratic sandstone; Tumbling Run--conglomeratic sandstone and sandstone.

Towamensing Member of Catskill Formation (Devonian) at surface, covers 2 % of this area

Dominantly gray sandstone and some siltstone and shale; freshwater fossils.

Beaverdam Run Member of Catskill Formation (Devonian) at surface, covers 2 % of this area

Alternating olive-gray siltstone and sandstone; marine fossils.

Berry Run and Sawmill Run Members of Catskill Formation, undivided (Devonian) at surface, covers 2 % of this area

Greenish-gray to gray sandstone and minor red siltstone and mudstone.

Bloomsburg Formation (Silurian) at surface, covers 2 % of this area

Grayish-red and greenish-gray shale, siltstone, and very fine to coarse-grained sandstone; some calcareous mudstone in central Pennsylvania; thins to west and is replaced by Mifflintown beds; thickens eastward, replacing overlying Wills Creek and Tonoloway Formations and underlying Mifflintown Formation.

Shawangunk Formation (Silurian) at surface, covers 2 % of this area

Light- to dark-gray, fine- to very coarse grained sandstone and conglomerate containing thin shale interbeds. Includes four members, in descending order: Tammany--conglomerate and sandstone; Lizard Creek--sandstone and red or green shale; Minsi--sandstone and conglomerate; Weiders--conglomerate. Tammany and Lizard Creek Members together are approximately equivalent to Clinton Group to the west; Minsi and Weiders Members together are equivalent to Tuscarora Formation to the west.

Clarks Ferry Member of Catskill Formation (Devonian) at surface, covers 1 % of this area

Gray to yellowish-gray sandstone and conglomerate.

Packerton Member of Catskill Formation (Devonian) at surface, covers 1 % of this area

Greenish-gray to gray sandstone and some siltstone; some laterally persistent conglomerate beds in lower part.

Decker Formation through Poxono Island Formation, undivided (Silurian) at surface, covers 0.7 % of this area

In descending order: Decker Formation--gray calcareous sandstone having lenses of calcareous conglomerate, siltstone, and shale, and lenses of limestone and dolomite (in Stroudsburg area, includes calcareous shale, limestone, and dolomite of Rondout Formation at top); Bossardville Limestone--gray argillaceous limestone and dolomitic limestone; Poxono Island Formation--thin-bedded dolomite, limestone, and shale; red shale in lower part. This undivided succession is equivalent to Keyser, Tonoloway, and Wills Creek (part) Formations of central Pennsylvania.

Clarks Ferry Member of Catskill Formation (Devonian) at surface, covers 0.7 % of this area

Gray to yellowish-gray sandstone, siltstone, and conglomerate.

Buttermilk Falls Limestone through Esopus Formation, undivided (Devonian) at surface, covers 0.5 % of this area

In descending order: Buttermilk Falls Limestone--gray fossiliferous limestone and black chert; Palmerton Sandstone--massive white siliceous sandstone; Schoharie Formation--gray calcareous, argillaceous siltstone; Esopus Formation--gray silty shale and sandy siltstone.

Ridgeley Formation through Coeymans Formation, undivided (Devonian) at surface, covers 0.5 % of this area

In descending order: Ridgeley Formation--white siliceous sandstone; Shriver Chert--gray siltstone and shale and dark-gray chert; Port Ewen Shale--dark-gray calcareous siltstone and shale; Minisink Limestone--dark-gray clayey limestone; New Scotland Formation--dark-gray fossiliferous shale and clayey limestone; Coeymans Formation--gray, clayey to sandy limestone.

Hamilton Group (Devonian) at surface, covers 0.3 % of this area

Includes, in descending order, the Mahantango (Dmh) and Marcellus (Dmr) Formations.

Onondaga and Old Port Formations, undivided (Devonian) at surface, covers < 0.1 % of this area

Includes, in descending order, the Onondaga Formation (Don), Ridgeley Member of Old Port Formation (Dor), and Shriver, Mandata, Corriganville, and New Creek Members of Old Port Formation, undivided (Dosn).

Martinsburg Formation (Ordovician) at surface, covers < 0.1 % of this area

Gray to dark-gray shale and slate.