Grayish-red, very fine to medium-grained, crossbedded sandstone, and grayish-red siltstone and shale; merges with underlying Bald Eagle Formation to the south; not present east of Susquehanna River, except at Spitzenberg Hill area (Berks County).
Light- to medium-gray quartzite and quartzitic sandstone and minor interbedded shale and siltstone, locally conglomeratic in lower part; includes (to the northwest) interbedded red and non-red sandstone (Castanea Member) at top; east of Harrisburg, equivalent to Minsi and Weiders Members of Shawangunk Formation.
Olive-gray to dark-gray shale, siltstone, and fine-grained, thin-bedded sandstone having graded bedding; upper sandstone is very fossiliferous; includes Antes Formation (black calcareous shale) at base along Nittany Arch.
Predominantly Rose Hill Formation--light-olive-gray to brownish-gray, fossiliferous shale; locally, limestone occurs near top; includes dark-reddish-gray, very fine to coarse-grained, ferruginous sandstone; east of Harrisburg, equivalent to Lizard Creek Member of Shawangunk Formation. Above Rose Hill is Keefer Formation--light- to dark-gray, fossiliferous sandstone, hematitic, oolitic sandstone, and shale; not recognized east of Harrisburg.
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).
Includes, in descending order, the Mahantango (Dmh) and Marcellus (Dmr) Formations.
In descending order: Keyser Formation--medium-gray, crystalline to nodular, fossiliferous limestone; upper part laminated and mud-cracked; not present east of Harrisburg; passes into lower Coeymans, Rondout, and Decker Formations in the east. Tonoloway Formation--medium-gray, laminated, mud-cracked limestone containing some medium-dark- or olive-gray shale interbeds; lower part passes into Wills Creek Formation east and south; passes into Bossardville and Poxono Island beds in the east.
Variegated gray, grayish-red, yellowish-gray and greenish-gray, interbedded calcareous shale, siltstone, shaly limestone, and dolomite; passes into Bloomsburg Formation in the southeast; not present east of Harrisburg.
Includes, in descending order, the Bloomsburg Formation (Sb) and the Mifflintown Formation--interbedded dark-gray shale and medium-gray fossiliferous limestone; equivalent to "McKenzie" and "Rochester" of earlier workers; not present east of Harrisburg.
Gray to olive-gray and grayish-red, fine- to coarse-grained, crossbedded sandstone, siltstone, and shale; some conglomerate (Lost Run Member); not present east of Susquehanna River, except at Spitzenberg Hill area (Berks County).
Medium-gray, brownish-weathering, medium-bedded dolomite and minor sandstone; very fine grained Tea Creek Member above, and crystalline Coffee Run Member below.
In descending order: Coburn Formation--medium-gray to very dark gray, very fossiliferous limestone and shaly limestone; Salona Formation--very dark gray to black, nonfossiliferous shaly limestone and calcareous shale containing metabentonite beds; Nealmont Formation--medium-gray fossiliferous limestone (calcarenite--Rodman Member) overlying thin-bedded shaly limestone (calcilutite--Center Hall Member).
In descending order: Benner Formation--light- to dark-gray, thick-bedded limestone (calcilutite); includes chemically pure Valentine Member (Obv) at top, and, below, the less pure Valley View Member, which contains metabentonite beds--all laterally equivalent to impure limestones of Oak Hall Member; Stover Member at base is dark-gray limestone (calcilutite) having dolomite streaks; Benner is called "Linden Hall" by some workers. Snyder Formation--light- to medium-gray limestone, laminated to medium-bedded; has mud cracks, oolites, and dolomitic layers. Hatter Formation--medium-gray, fossiliferous, argillaceous limestone, laminated and dolomitic. Loysburg Formation--light- to medium-gray, medium-bedded limestone (Clover Member) overlying laminated, alternating limestone, dolomitic limestone, and dolomite (Milroy ["tiger-striped"] Member).
Medium-gray fossiliferous limestone.
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.