Table 1a. Generalized stratigraphy of Appalachian basin Total Petroleum Systems (adapted from de Witt and Milici, 1991, fig. 2). TOTAL STRATIGRAPHIC ASSESSMENT RESERVOIR SOURCE PETROLEUM UNIT UNIT TYPE ROCK ERA SYSTEM PERIOD Dunkard Group ian Perm- Coal Monongahela Continuous Coal Group sandstone Black shale Conemaugh Coal Coal ANIAN Continuous V Group sandstone Black shale Carboniferous Coal-bed Gas LITHOLOGY OF Allegheny Coal Coal Continuous Group sandstone Black shale SOURCE ROCK PENNSYL Pottsville Coal Coal OR RESERVOIR Continuous Group sandstone Black shale Mauch Chunk / Ravencliff sand Pennington Conventional Coal, black shale, Formations Maxon sand Greenbrier Loyalhanna sand and sandstone Conventional Limestone Big lime Pocono Big Injun, Squaw, Conventional Formation Weir sands C I Black shale and coal MISSISSIPPIAN Berea / Murrysville Berea sand Sunbury Continuous Murrysville sand Sandstones Shale Catskill, Brallier Fms., Venango, Bradford, Sandstone Cleveland, Elk sands; Continuous Upper Devonian Ohio, Huron, O black shales black shale Rhinestreet Shales Limestone Continuous Harrell Formation Black shale Burket Member Hamilton Group Black shale Continuous Marcellus Shale Z Onondaga Group DEVONIAN Huntersville Chert Conventional Dolomite Huntersville Chert "Corniferous" lime Oriskany Ss. Oriskany sands Conventional Helderberg Group O Bass Islands Dolomite Salina Group Regional seal Lockport Dolomite "Corniferous" lime Clinton Group Keefer or Big Six Continuous SILURIAN sand Medina Tuscarora/Clinch Ss. Continuous Group Clinton/Medina sand E Juniata/Bald Bald Eagle sand Eagle Fms. Reedsville Shale Utica Shale Utica Shale Continuous Utica Shale Devonian Shale-Middle and Upper Paleozoic L A Trenton Trenton Limestone Trenton Limestone Conventional Limestone ORDOVICIAN Black River Black River Ls., Conventional Sevier/ Limestone Wells Creek fm. Blockhouse Sh. Utica-Lower Paleozoic P Beekmantown Group Upper Knox Dol. Conventional Chepultepec and Rose Run sand, Conventional Copper Ridge Dols. Lower Knox, Dol. Conasauga Conasauga Formation / Group Formation Rome Formation Rome Formation Mt. Simon Basal Clastics Sandstone Conasauga-Rome/Conasauga CAMBRIAN .