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.
Predominantly greenish gray, gray, purple, and maroon shale, siltstone, and graywacke; includes some wildflysch having Martinsburg matrix.
Alternating grayish-red mudstone and siltstone in poorly defined fining-upward cycles, and minor intervals of gray sandstone; laterally equivalent to Berry Run, Sawmill Run, Packerton, and Long Run Members of eastern Pennsylvania.
Reddish-brown to maroon, silty mudstone and shale containing thin red sandstone interbeds; several thin beds of impure limestone.
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.
Grayish-red sandstone, siltstone, and mudstone in fining-upward cycles; conglomerate occurs at base of some cycles.
Nonmarine, grayish-red siltstone and mudstone, and gray and grayish-red sandstone interbedded with minor, thin, light-olive-gray marine siltstone; arranged in fining-upward cycles. Lower part of member has conglomeratic sandstones.
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.
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.
Very finely crystalline, light-gray limestone interbedded with gray dolomite; coarsely crystalline limestone lenses present.
Medium- to coarse-grained, quartz-normative tholeiite; composed of labradorite and various pyroxenes; occurs as dikes, sheets, and a few small flows. Includes the dark-gray York Haven Diabase (high titanium oxide) and the slightly younger Rossville Diabase (low titanium oxide). In chilled margins, the Rossville is distinguished from the York Haven by its lighter gray color and distinctive, sparse, centimeter-sized calcic-plagioclase phenocrysts.
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.
Gray to yellowish-gray sandstone, siltstone, and conglomerate.
Very finely crystalline, "birdseye" limestone at top and base, granular fossiliferous limestone, black chert, and dolomite in middle.
Includes, in descending order, the Mahantango (Dmh) and Marcellus (Dmr) Formations.
Gray, fine- to coarse-grained sandstone, siltstone, shale, conglomerate, and numerous anthracite coals in repetitive sequences.
Gray to dark-gray, buff-weathering shale.
Dark-gray, thin-bedded, platy argillaceous limestone containing some beds of shale.
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.
Gray, finely crystalline limestone containing dark-gray silty laminations; numerous edgewise conglomerate beds.
In descending order: Hershey--dark-gray to black, thin-bedded, argillaceous limestone; Myerstown--medium- to dark-gray, platy, medium-crystalline limestone; carbonaceous at base.
Light- to dark-gray, very finely to medium-crystalline dolomite containing interbeds of light-gray limestone; interbedded nodular, dark-gray chert at base.
Light-gray to pinkish-gray, finely to coarsely crystalline limestone and interbedded dolomite; numerous siliceous and clayey laminae; stromatolitic limestone beds near top; some thin sandy beds.
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.
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.
Gray quartz conglomerate, sandstone, and red siltstone and mudstone.
Light-gray, massive, high-calcium limestone; mottled at base.
Light-colored, thick-bedded, finely laminated dolomite; some limestone.
Dark-gray, cobbly, argillaceous limestone; abundant irregular shale partings; some metabentonite beds present.
Gray and pale red, fine- to coarse-grained quartzose sandstone, siltstone, and mudstone.
Mostly limestone; some dolomite interbeds; some chert near middle and top; stromatolitic limestone in middle; pinkish marbleoid limestone and chert at base.
Yellowish-gray to medium-gray, angular limestone and dolomite pebbles, cobbles, and fragments set in a red, very fine grained quartz matrix; a few shale-clast interbeds.
Light-gray to buff, commonly arkosic sandstone interbedded with red shale, mudstone, and fine-grained sandstone
Cobble and pebble quartz conglomerate interbedded with red sandstone.