Geologic units in Pike county, Pennsylvania

Long Run and Walcksville Members of Catskill Formation, undivided (Devonian) at surface, covers 68 % of this area

Includes, in descending order, the Long Run (Dclr) and Walcksville (Dcw) Members of the Catskill Formation, which are described separately below.

Poplar Gap and Packerton Members of Catskill Formation, undivided (Devonian) at surface, covers 10 % of this area

Includes, in descending order, the Poplar Gap (Dcpg) and Packerton (Dcp) Members of the Catskill Formation.

Mahantango Formation (Devonian) at surface, covers 8 % 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.

Towamensing Member of Catskill Formation (Devonian) at surface, covers 8 % of this area

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

Trimmers Rock Formation (Devonian) at surface, covers 5 % 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 0.6 % 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 0.2 % of this area

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

Lower Walton Formation (Upper Devonian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate.

Catskill Formation (Devonian) at surface, covers < 0.1 % of this area

Grayish-red sandstone, siltstone, shale, and mudstone; units of gray sandstone occur in upper part; lithologies in upper part arranged in fining-upward cycles. In the Altoona area, the Catskill Formation is mapped as the Duncannon, Sherman Creek, and Irish Valley Members, which are described under "Central and Eastern Pennsylvania" provinces.

Marcellus Shale (Middle Devonian) at surface, covers < 0.1 % of this area

(Vanuxem, 1840) - Medium-gray weathering, dark-gray to grayish-black, thin- to thick-bedded, fossiliferous, fissile and limonite-stained locally arenaceous shale. Lower contact grades downward over 12 m (40 ft) from black shale through limy shale, into silty limestone of the Buttermilk Falls Limestone (documented in drill core data of Fletcher and Woodrow, 1970). Approximately 274 m (900 ft) thick.

Honesdale Formation (Upper Devonian) at surface, covers < 0.1 % of this area

Sandstone, shale.

Undifferentiated Hamilton Group (Middle Devonian) at surface, covers < 0.1 % of this area

Shale, siltstone. In eastern Orange County: Skunnemunk Formation-sandstone, conglomerate; Bellvale Formation-shale, sandstone; Cornwall Shale.

Buttermilk Falls Limestone and Onondaga Limestones, undivided (Middle Devonian) at surface, covers < 0.1 % of this area

Buttermilk Falls Limestone in southwestern part of outcrop belt grades into Onondaga Limestone along strike to northeast. The transition occurs north of Millville. Buttermilk Falls Limestone (Middle Devonian) (Willard, 1938) - Light- to medium-light-gray-weathering, medium- to dark-gray, thin- to medium-bedded, fossiliferous, flaggy, clayey to silty limestone and nodular black chert. Lower contact grades downward through several meters (feet) of silty limestone to interbedded limestone and calcareous siltstone of the Schoharie Formation. Thickness is approximately 82 m (270 ft). Onondaga Limestone (Middle Devonian) (Vanuxem 1840) - Light-medium-gray- weathering, medium gray, fine-grained, thin- to thick-bedded fossiliferous limestone. Black chert more abundant in upper half of unit. Lower contact grades into interbedded limestone and calcareous siltstone of the Schoharie Formation. Thickness approximately 60 m (200ft).

Upper Walton Formation (Upper Devonian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate.

Oneonta Formation (Middle - Upper Devonian) at surface, covers < 0.1 % of this area

Shale, sandstone, conglomerate.

Onondaga Limestone (Lower to Middle Devonian) at surface, covers < 0.1 % of this area

Seneca, Morehouse (cherty), and Nedrow Limestone Members, Edgecliff cherty Limestone Member, local bioherms, Buttermilk Falls Limestone Member; Schoharie Formation-shale, limestone; Carlisle Center Siltstone; Esopus Shale.

Schoharie Formation (Lower Devonian) at surface, covers < 0.1 % of this area

(Vanuxem, 1840) - Yellowish-gray- to locally pale-olive-weathering, medium- to dark-gray, medium- to thick-bedded, calcaeous siltstone and lesser amounts of silty limestone. Locally contains thin ribs or pods of black chert in limestone. Limestone content decreases in lower part of unit. Contains the trace fossil Taonurus, a grazing trail. Lower contact gradational and placed at top of highest massive siltstone below lowest limestone. Thickness approximately 53 m (175 ft).

Buttermilk Falls Limestone through Esopus Formation, undivided (Devonian) at surface, covers < 0.1 % 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.

Slide Mountain Formation (Upper Devonian) at surface, covers < 0.1 % of this area

Sandstone, shale, conglomerate.