| Ca - Antietam Formation |
| Cah - Antietam and Harpers Formation, undivided |
| Cal - Allentown Formation |
| Cbs - Buffalo Springs Formation |
| Cch - Chickies Formation |
| Ce - Elbrook Formation |
| Cg - Gatesburg Formation |
| Cgl - Lower Members of Gatesburg Formation, undivided |
| Cgm - Mines Member of Gatesburg Formation |
|
| Ch - Harpers Formation |
| Cha - Hardyston Formation |
| Chm - Montalto Member of Harpers Formation |
| Ck - Kinzers Formation |
|
| Cl - Ledger Formation |
| Clv - Leithsville Formation |
| Cm - Millbach Formation |
| Cms - Millbach and Schaefferstown Formations, undivided |
| Cph - Pleasant Hill Formation |
|
| Cr - Richland Formation |
| Csb - Snitz Creek and Buffalo Springs Formations, undivided |
| Csc - Snitz Creek Formation |
| Csg - Shadygrove Formation |
| Ct - Tomstown Formation |
| Cul - Lower (Middle?) Cambrian rocks, undivided |
| Cv - Vintage Formation |
| Cw - Warrior Formation |
|
| Cwb - Waynesboro Formation |
| Cwl - Weverton and Loudoun Formations, undivided |
| Cz - Zullinger Formation |
| Czc - Zooks Corner Formation |
| DSkc - Keyser Formation through Clinton Group, undivided |
| DSkm - Keyser Formation through Mifflintown Formation, undivided |
| DSkt - Keyser and Tonoloway Formations, undivided |
| DSop - Onondaga Formation through Poxono Island Formation, undivided |
| Dbe - Buttermilk Falls Limestone through Esopus Formation, undivided |
|
| Dbh - Brallier and Harrell Formations, undivided |
| Dbr - Berea Sandstone through Riceville Formation, undivided |
| Dbv - Berea Sandstone through Venango Formation, undivided |
|
| Dcb - Buddys Run Member of Catskill Formation |
| Dcbr - Beaverdam Run Member of Catskill Formation |
| Dcbs - Berry Run and Sawmill Run Members of Catskill Formation, undivided |
|
| Dccf - Clarks Ferry Member of Catskill Formation |
| Dcd - Duncannon Member of Catskill Formation |
|
| Dch - Chadakoin Formation |
|
| Dciv - Irish Valley Member of Catskill Formation |
| Dck - Catskill Formation |
|
| Dclr - Long Run Member of Catskill Formation |
|
| Dclw - Long Run and Walcksville Members of Catskill Formation, undivided |
|
| Dcp - Packerton Member of Catskill Formation |
| Dcpg - Poplar Gap Member of Catskill Formation |
|
| Dcpp - Poplar Gap and Packerton Members of Catskill Formation, undivided |
|
| Dcr - Corry Sandstone through Riceville Formation, undivided |
|
| Dcsc - Sherman Creek Member of Catskill Formation |
| Dct - Towamensing Member of Catskill Formation |
|
| Dcw - Walcksville Member of Catskill Formation |
|
| Dcwt - Walcksville and Towamensing Members of Catskill Formation, undivided |
| Df - Foreknobs Formation |
| Dg - Girard Shale |
|
| Dh - Hamilton Group |
|
| Dlh - Lock Haven Formation |
| Dm - Marcellus Formation |
| Dmh - Mahantango Formation |
|
| Dne - Northeast Shale |
|
| Don - Onondaga Formation |
|
| Doo - Onondaga and Old Port Formations, undivided |
| Dor - Ridgeley Member of Old Port Formation |
|
| Dosn - Shriver, Mandata, Corriganville, and New Creek Members of Old Port Formation, undivided |
|
| Drc - Ridgeley Formation through Coeymans Formation, undivided |
|
| Ds - Scherr Formation |
|
| Dtr - Trimmers Rock Formation |
|
| Dv - Venango Formation |
| Jd - Diabase |
| Js - Sedimentary strata at Jacksonwald and Aspers |
| Kp - Patapsco(?) Formation |
|
| MDhm - Huntley Mountain Formation |
| MDpr - Pocono and Rockwell Formations, undivided |
|
| MDr - Rockwell Formation |
|
| MDsk - Spechty Kopf Formation |
| MDso - Shenango Formation through Oswayo Formation, undivided |
|
| MDsr - Shenango Formation through Riceville Formation, undivided |
| Mb - Burgoon Sandstone |
|
| Mbc - Burgoon Sandstone through Cuyahoga Group, undifferentiated |
| Mc - Cuyahoga Group |
| Mmc - Mauch Chunk Formation |
|
| Mp - Pocono Formation |
| Ms - Shenango Formation |
|
| Msc - Shenango Formation through Cuyahoga Group, undivided |
| OCc - Conestoga Formation |
| Oa - Axemann Formation |
| Oan - Annville Formation |
| Ob - Beekmantown Group |
|
| Oba - Bellefonte and Axemann Formations, undivided |
| Obe - Bald Eagle Formation |
| Obf - Bellefonte Formation |
|
| Obl - Benner Formation through Loysburg Formation, undivided |
| Obv - Valentine Member of Benner Formation |
| Oc - Chambersburg Formation |
| Ocl - Coburn Formation through Loysburg Formation, undivided |
|
| Ocn - Coburn Formation through Nealmont Formation, undivided |
| Oco - Cocalico Formation |
|
| Oe - Epler Formation |
|
| Oh - Hamburg sequence rocks |
|
| Oha - Hershey Formation through Annville Formation, undivided |
| Ohg - Graywacke of Hamburg sequence |
|
| Ohjv - Jonestown Volcanic Suite |
|
| Ohl - Limestone of Hamburg sequence |
|
| Ohm - Hershey and Myerstown Formations, undivided |
|
| Ohsg - Shale and graywacke of Hamburg sequence |
|
| Oj - Juniata Formation |
|
| Ojb - Juniata and Bald Eagle Formations, undivided |
|
| Ojk - Jacksonburg Formation |
| Om - Martinsburg Formation |
|
| Omgs - Graywacke and shale of Martinsburg Formation |
| Oml - Limestone of Martinsburg Formation |
| On - Nittany Formation |
|
| Ons - Nittany and Stonehenge/Larke Formations, undivided |
|
| Oo - Ontelaunee Formation |
| Ops - Pinesburg Station Formation |
|
| Or - Reedsville Formation |
| Ori - Rickenbach Formation |
| Orr - Rockdale Run Formation |
| Os - Stonehenge Formation |
| Osl - Stonehenge/Larke Formation |
| Osp - St. Paul Group |
| PPw - Waynesburg Formation |
| Pa - Allegheny Formation |
|
| Pap - Allegheny and Pottsville Formations, undivided |
|
| Pc - Conemaugh Group |
|
| Pcc - Casselman Formation |
|
| Pcg - Glenshaw Formation |
| Pg - Greene Formation |
|
| Pl - Llewellyn Formation |
|
| Pm - Monongahela Group |
| Pp - Pottsville Formation |
| Pw - Waynesburg Formation |
| Qs - Sands of Presque Isle |
|
| Qt - Trenton Gravel |
|
| Sb - Bloomsburg Formation |
|
| Sbm - Bloomsburg and Mifflintown Formations, undivided |
|
| Sc - Clinton Group |
|
| Sdp - Decker Formation through Poxono Island Formation, undivided |
| Ss - Shawangunk Formation |
| St - Tuscarora Formation |
|
| Swc - Wills Creek Formation |
|
| Swm - Wills Creek Formation through Mifflintown Formation, undivided |
| Tbm - Bryn Mawr Formation |
| Tpb - Pensauken and Bridgeton Formations, undifferentiated |
|
| Trb - Brunswick Formation |
|
| Trfl - Limestone fanglomerate |
| Trfq - Quartz fanglomerate |
|
| Trg - Gettysburg Formation |
| Trgc - Gettysburg conglomerate |
|
| Trgh - Heidlersburg Member of Gettysburg Formation |
|
| Trh - Hammer Creek Formation |
|
| Trhc - Hammer Creek conglomerate |
|
| Trl - Lockatong Formation |
|
| Trn - New Oxford Formation |
| Trnc - New Oxford conglomerate |
|
| Trs - Stockton Formation |
|
| Trsc - Stockton conglomerate |
| Xa - Anorthosite |
| Xc - Cockeysville Marble |
|
| Xgr - Granitic gneiss and granite |
| Xgw - "Glenarm Wissahickon" formation |
|
| Xm - Marburg Schist |
|
| Xmg - Metagabbro |
|
| Xmgh - Mafic gneiss |
| Xmgp - Mafic gneiss |
|
| Xo - Octoraro Formation |
| Xpb - Peach Bottom Slate and Cardiff Conglomerate, undivided |
|
| Xpc - Peters Creek Schist |
| Xpg - Pegmatite |
| Xsc - Sams Creek Metabasalt |
|
| Xsq - Setters Quartzite |
| Xu - Ultramafic rocks |
|
| Xw - Wissahickon Formation |
| Xwk - Wakefield Marble |
|
| a - Anorthosite |
|
| fgh - Felsic and intermediate gneiss |
|
| fgp - Felsic gneiss |
| fm - Franklin Marble |
| gg - Graphitic felsic gneiss |
| gga - Banded mafic gneiss |
|
| ggd - Felsic and intermediate gneiss |
|
| gn - Felsic to mafic gneiss |
| gqm - Graphitic felsic gneiss |
|
| hg - Hornblende gneiss |
| mb - Metabasalt |
| md - Metadiabase |
| mgh - Mafic gneiss |
|
| mgp - Mafic gneiss |
|
| mr - Metarhyolite |
| vs - Greenstone schist |
