| PIPd - Dunkard Group |
| IPm - Monongahela Group |
| IPc - Conemaugh Group |
| IPap - Allegheny and Pottsville Groups, undifferentiated |
| Mlc - Logan and Cuyahoga Formations undivided |
| Mcb - Black Hand Member of the Cuyahoga Formation |
| Mc - Coldwater Shale |
| Ms - Sunbury Shale |
| MDs - Sunbury and Bedford Shales undivided |
| MDsb - Sunbury Shale, Berea Sandstone, and Bedford Shale, undivided |
| MDu - Mississippian and Devonian undifferentiated |
| Dbb - Berea Sandstone and Bedford Shale, undivided |
| Da - Antrim Shale |
| Doh - Ohio Shale |
| Do - Olentangy Shale |
| Dp - Prout Limestone |
| Dpl - Plum Brook Shale |
| Dts - Ten Mile Creek Dolomite and Silica Formation, undivided |
| Dd - Delaware Limestone |
| Ddu - Dundee Limestone |
| Dc - Columbus Limestone |
| Dcd - Columbus Limestone and Detroit River Group, undivided |
| Ddr - Detroit River Group |
| Ss - Salina Group |
| Stg - Tymochtee and Greenfield Dolomites, undivided |
| Sc - Clinton and Cataract Groups, undifferentiated |
| Sl - Lockport Dolomite |
| Spb - Peebles Dolomite, and Lilley and Bisher Formations, undivided |
| Scl - Cedarville, Springfield, and Euphemia Dolomites, Massie Shale, and Laurel Dolomite, undivided |
| Sce - Cedarville, Springfield, and Euphemia Dolomites, undivided |
| Sdb - Dayton Limestone and Brassfield Formation, undivided |
| Sed - Estill Shale and Drowning Creek Formation, undivided |
| Se - Estill Shale |
| Sd - Drowning Creek Formation |
| Smb - Massie Shale, Laurel Dolomite, Osgood Shale, Dayton Limestone, and Brassfield Formation, undivided |
| Ou - Ordovician Undifferentiated |
| Oc - Cincinnati Group |
| Oda - Preachersville Member of the Drakes Formation, Waynesville Formation, and Arnheim shale and limestone, undivided |
| Odl - Drakes, Whitewater, Saluda, and Liberty Formations, undivided |
| Owa - Waynesville Formation and Arnheim shale and limestone undivided |
| Ogf - Grant Lake and Fairview Formations, undivided |
| Ogm - Grant Lake Formation, Miamitown Shale, and Fairview Formation, undivided |
| Ogl - Grant Lake Limestone and Fairview Formation, undivided |
| Ok - Kope Formation |
| Op - Point Pleasant Formation |
