The following is a list of the mapped bedrock units in Pennsylvania. The rocks are listed in stratigraphic order.Berg, T.M., et al., (1983). Stratigraphic Correlation Chart of Pennsylvania: G75, Pennsylvania Geologic Survey, Harrisburg, Pennsylvania.
System Group name Formation name Member name Map symbolBerg, 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. 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/EdiacaranBlackmer, 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. 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
See also Geology of Pennsylvania