List of mapped rock formations in Pennsylvania

This list is incomplete; you can help by adding missing items. (August 2008)

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The following is a list of the mapped bedrock units in Pennsylvania. The rocks are listed in stratigraphic order.[1]

System  | Group name  | Formation name  | Member name  | Map symbol[2]

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Triassic | Newark Group | Passaic Formation |  | Trp
Triassic  | Newark Group  | Lockatong Formation |  | Trl
Triassic  | Newark Group  | Stockton Formation |  | Trs
Permian | Dunkard Group | Greene Formation |  | Pg
Permian  | Dunkard Group  | Washington Formation |  | Pw
Pennsylvanian | Conemaugh Group | Casselman Formation |  | φcc
Pennsylvanian  | Conemaugh Group  | Glenshaw Formation |  | φcg
Pennsylvanian  |  | Allegheny Formation |  | φa
Pennsylvanian  |  | Llewellyn Formation |  | φl
Pennsylvanian  |  | Pottsville Formation |  | φp
Mississippian |  | Mauch Chunk Formation |  | Mmc
Mississippian  |  | Pocono Formation
(Burgoon Formation)  |  | Mp
(Mb)
Mississippian/Devonian  |  | Spechty Kopf Formation |  |
Mississippian/Devonian  |  | Rockwell Formation |  |
Mississippian/Devonian  |  | Huntley Mountain Formation |  |
Devonian |  | Catskill Formation |  | Dck
Devonian  |  | Brallier Formation |  | Db
Devonian  |  | Harrell Formation |  | Dh
Devonian  | Hamilton Group | Mahantango Formation |  | Dmh
Devonian  | Hamilton Group  | Marcellus Formation |  | Dm
Devonian  |  | Onondaga Formation |  | Do
Devonian  |  | Old Port Formation |  | Dop
Devonian  |  | Old Port Formation  | Ridgeley Member | Dr
Devonian/Silurian  |  | Keyser Formation |  | DSk
Silurian |  | Tonoloway Formation |  | Sto
Silurian  |  | Wills Creek Formation |  | Swc
Silurian  |  | Bloomsburg Formation |  | Sb
Silurian  |  | Mifflintown Formation |  | Sm
Silurian  | Clinton Group | Keefer Formation |  | Sk
Silurian  | Clinton Group  | Rose Hill Formation |  | Srh
Silurian  |  | Tuscarora Formation |  | St
Silurian  |  | Shawangunk Formation |  | Ss
Ordovician |  | Juniata Formation |  | Oj
Ordovician  |  | Bald Eagle Formation |  | Obe
Ordovician  |  | Reedsville Formation |  | Or
Ordovician  |  | Martinsburg Formation |  | Om
Ordovician  | Trenton Group | Coburn Formation |  |
Ordovician  | Trenton Group  | Salona Formation |  |
Ordovician  | Trenton Group  | Nealmont Formation |  |
Ordovician  |  | Benner Formation |  | Om
Ordovician  |  | Bellefonte Formation |  | Obf
Ordovician  |  | Axeman Formation |  | Oa
Ordovician  |  | Nittany Formation |  | On
Ordovician  |  | Stonehenge/Larke Formation |  | Osl
Cambrian |  | Warrior Formation |  | Cw
Cambrian  |  | Chickies Formation |  | Cch
Cambrian/Ediacaran[3] |  | Wissahickon Formation |  | CZw
Mesoproterozoic Era |  | Baltimore Gneiss |  | Ybg

Note: Some of the Formations are laterally equivalent in age. They are listed in order from West to East in this case.

## References

[edit]

1. ^ Berg, T.M., et al., (1983). Stratigraphic Correlation Chart of Pennsylvania: G75, Pennsylvania Geologic Survey, Harrisburg, Pennsylvania.
2. ^ Berg, T.M., Edmunds, W.E., Geyer, A.R. and others, compilers, (1980). Geologic Map of Pennsylvania: Pennsylvania Geologic Survey, Map 1, scale 1:250,000.
3. ^ Blackmer, G.C., (2005). Preliminary Bedrock Geologic Map of a Portion of the Wilmington 30- by 60-Minute Quadrangle, Southeastern Pennsylvania. Pennsylvania Geologic Survey, Open-File Report OFBM-05-01.0.

## See also

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* Geology of Pennsylvania