| Approximate limit of Sg |
| Approximate limit of mappable Greenfield Dolomite and Tymochtee Dolomite |
| Eastern limit of Scse |
| Eastern mappable limit of Odwhl, Ow, Oa, Ogl, and Of |
| Limit of Ms - Mc |
| Limit of Omf |
| Limit of Sc-l and Splb |
| Limit of the Ames Limestone |
| Line separating Mlc - Mc |
| Line separating Odw, Odwl, and Ow |
| Line separating the Owa and Ow |
| Mappable limit of Saluda formation |
| Mapping limit of Serpent Mound structure |
| Northern and western limit of Greenfield and Peebles Dolomite, and Lilley Bisher undivided |
| Northern mappable limit of Odwl, Ow, Oa, and Ogl |
| Ogl - Ogll transition |
| Southern and western limit of Salina undifferentiated rocks |
| Southern limit of Dol, Dd |
| Southern limit of Owa |
| Western limit of Scse and Sm-b |
| Western limit of Splb |
| Western limit of Ssu, Scse, and Sm-b |
| Qal - Alluvium |
| Qac - Lithified Stream Deposits (Peebles Quadrangle Only) |
| Qt2 - Second Terrace Deposits (Peebles Quadrangle Only) |
| Qt1 - First Terrace Deposits (Peebles Quadrangle Only) |
| Pd - Dunkard Group (Permian) |
| PIPd - Dunkard Group (Permian-Pennsylvanian) |
| IPm - Monongahela Group |
| IPc - Conemaugh Group |
| IPa - Allegheny Group |
| IPap - Allegheny And Pottsville Groups Undivided |
| IPb - Breathitt Group |
| Mu - Maxville Limestone, Logan Formation, And Cuyahoga Formations Undivided |
| Msbd - Sunbury And Bedford Formations Undivided |
| Mlc - Logan And Cuyahoga Formations Undivided |
| Mc - Cuyahoga Formation |
| Mc-d - Cuyahoga Formation, Sunbury Shale, Berea Sandstone, Bedford Shale Undivided (Serpent Mound Only) |
| Ms-d - Sunbury Shale, Berea Sandstone, And Bedford Shale Undivided (Michigan Basin Only) |
| Ms - Sunbury Shale |
| Mcw - Coldwater Shale |
| Mbbd - Berea Sandstone And Bedford Shale Undivided |
| Mb - Berea Sandstone |
| Mbd - Bedford Shale |
| DMu - Sunbury Shale, Berea Sandstone, And Bedford Shale Undivided |
| Do - Ohio And Olentangy Shales Undivided |
| Doh - Ohio Shale |
| Da - Antrim Shale |
| Dol - Olentangy Shale |
| Dolp - Prout Limestone Member |
| Dolpb - Plum Brook Shale Member |
| Dt - Traverse Group |
| Dd - Delaware Limestone |
| Ddd - Dundee Limestone |
| Dcl - Columbus And Lucas Undifferentiated |
| Dc - Columbus Limestone |
| Ddr - Detroit River Group |
| Sbi - Bass Islands Dolomite |
| Ssg - Salina Group |
| Ssu - Salina Undifferentiated |
| St - Tymochtee Dolomite |
| Stg - Tymochtee And Greenfield Formations Undivided |
| Sg - Greenfield Dolomite |
| Sl - Lockport Dolomite |
| Sbr - Bisher Dolomite |
| Slb - Lilley And Bisher Formations Undivided (Serpent Mound Only) |
| Stgp - Tymochtee, Greenfield, And Peebles Dolomites Undivided (Serpent Mound Only) |
| St-b - Tymochtee Dolomite, Greenfield Dolomite, And Peebles Dolomite, Lilley Formation, And Bisher Formation Undivided |
| Splb - Peebles Dolomite, Lilley Formation, Bisher Formation Undivided |
| Sp - Peebles Dolomite |
| Sli - Lilley Formation |
| Sc-l - Cedarville Dolomite, Springfield Dolomite, Euphemia Dolomite, Massie Shale, Laurel Dolomite Undivided |
| Scse - Cedarville Dolomite, Springfield Dolomite, Euphemia Dolomite Undivided |
| Sdb - Dayton And Brassfield Formations Undivided |
| Se - Estill Shale |
| Snb - Noland And Brassfield Formations Undivided (Peebles Quadrangle Only) |
| Sdnb - Dayton Limestone, Noland Formation And Brassfield Undivided |
| Sm-b - Massie Shale, Laurel Dolomite, Osgood Shale, Dayton Limestone, And Brassfield Limestone Undivided |
| Sb - Brassfield Formation |
| Ssl - Sub-Lockport Undifferentiated |
| Ou - Ordovician Undivided |
| Odp - Preachersville Member |
| Odw - Drakes Formation And Waynesville Formation Undivided |
| Odwl - Drakes Formation, Whitewater Formation, And Liberty Formation Undivided |
| Od - Drakes Formation |
| Os - Saluda Formation |
| Owa - Waynesville Formation And Arnheim Formations Undivided |
| Obf - Bull Fork Formation (Peebles Quadrangle Only) |
| Ow - Waynesville Formation |
| Oa - Arnheim formation |
| Oglf - Grant Lake Formation |
| Ogll - Grant Lake Limestone |
| Ogfl - Grant Lake Formation And Grant Lake Limestone Undifferentiated |
| Ogls - Straight Creek Member |
| Oglc - Corryville Member |
| Oglu - Straight Creek And Corryville Members Undivided |
| Oglb - Bellevue Member |
| Omf - Miamitown Shale-Fairview Formation Undivided |
| Of - Fairview Formation |
| Ok - Kope Formation |
| Op - Point Pleasant Formation |