"Bogota Limestone Member" "Boles Member" "Bond Formation" "Bonpas Limestone Member" "Borden Siltstone" "Brainard Shale" "Brandon Bridge Member" "Breezy Hill Limestone Member" "Brereton Limestone Member" "Briar Hill Coal Member" "Brickeys Member" "Briton Member" "Brush Coal Member" "Buckhorn Member" "Buelter Member" "Bunje Limestone Member" "Burlington Limestone" "Burroughs Limestone Member" "Cahokia Alluvium" "Calhoun Coal Member" "Cambrian System" "Canadian Series" "Canteen member" "Canton Shale Member" "Cape Limestone" "Capron Till Member" "Carbondale Formation" "Cardiff coal bed" "Carlinville Limestone Member" "Caseyville Formation" "Castlewood Member" "Cave Hill Shale Member" "Cayugan Series" "Cedar Bluff Limestone Group" "Cedar Valley Limestone" "Cenozoic Erathem" "Chalfin Member" "Champlainian Series" "Chana Member" "Chapel Coal Member" "Chapin Soil" "Charter Member" "Chazyan Stage" "Cheltenham Clay Member" "Chesterian Series" "Chouteau Limestone" "Cincinnatian Series" "Clayton Formation" "Clear Creek Chert" "Clement Member" "Clermont Shale Member" "Clore Formation" "Coffeen Limestone Member" "Coggan Member" "Cohn Coal Member" "Colchester Coal Member" "Conant Limestone Member" "Cooper Limestone Member" "Copperas Creek Sandstone Member" "Cora Limestone Member" "Coralville Member" "County Line (Alburnett) silt" "Covel Conglomerate Bed" "Coxville Sandstone Member" "Cramer Limestone Member" "Crane Member" "Creal Springs Limestone Member" "Cretaceous System" "Croixan Series" "Crowleys Ridge Silt" "Curlew Limestone Member" "Cypress Sandstone" "Dane Member" "Danville Coal Member" "Davenport Member" "Davis Coal Member" "Davis Member" "Daysville Dolomite Member" "De Graff Coal Member" "De Long Coal Member" "Decorah Subgroup" "Defiance Member" "Degonia Sandstone" "Dekoven Coal Member" "Delafield Member" "Delavan Member" "Delwood Coal Member" "Dement Member" "Derby-Doerun Member" "Desmoinesian Series" "Devonian System" "Dix Limestone Member" "Dolton Member" "Downeys Bluff Limestone" "Dresbachian Stage" "Drummond Member" "Dubuque Formation" "Duncan Mills Member" "Dunleith Formation" "Dutch Creek Sandstone Member" "Dutchtown Limestone" "Dykersburg Shale Member" "Eagle Point Member" "Eastern Granite-Rhyolite Province (Basement)" "Eau Claire Formation" "Edenian Stage" "Edgewood Formation" "Effingham Limestone Member" "Eldena Member" "Elgin Shale Member" "Elm Member" "Elmhurst Sandstone Member" "Elviran Stage" "Elwood Formation" "Embayment Megagroup" "Eminence Formation" "Energy Shale Member" "Enion Formation" "Eocene Series" "Equality Formation" "Esmond Till Member" "Establishment Member" "Everett Member" "Everton Dolomite" "Excello Shale Member" "Exline Limestone Member" "Fairplay Member" "Farmdale Soil" "Farmington Shale Member" "Fern Glen Formation" "Finnie Sandstone Member" "Flannigan Coal Member" "Flat Creek Coal Member" "Ford Station Limestone Member" "Forreston Member" "Fort Atkinson Limstone" "Fort Payne Formation" "Fox Valley Member" "Fraileys Shale" "Francis Creek Shale Member" "Franconia Formation" "Franconian Stage" "Fredonia Limestone Member" "Friendsville Coal Member" "Fults Member" "Galatia Member" "Galena Group" "Galesville Sandstone" "Galum Limestone Member" "Garnavillo Member" "Gasperian Stage" "Geneva Dolomite Member" "Genevievian Stage" "Gentry Coal Bed" "Gila Limestone Member" "Gimlet Sandstone Member" "Girardeau Limestone" "Glasford Formation" "Glen Dean Limestone" "Glen Park Formation" "Glenburn Till Member" "Glencoe Member" "Glenhaven Member" "Glenwood Formation" "Golconda Group" "Gordonville Member" "Goreville Limestone Member" "Grand Detour Formation" "Grand Tower Limestone" "Granger Sandstone Member" "Grassy Creek Shale" "Grassy Knob Chert" "Grayslake Peat" "Greenbush Coal Member" "Greenup Limestone Member" "Grigg tongue" "Grindstaff Sandstone Member" "Grove Church Shale" "Grover Gravel" "Gulfian Series" "Gunn Member" "Gunter Sandstone" "Guttenberg Formation" "Hadley Gravel Member" "Haeger Member" "Hagarstown Member" "Hall Limestone Member" "Haney Limestone" "Hannibal Shale" "Hanover Limestone Member" "Hardinsburg Sandstone" "Harkness Silt Member" "Harmattan Till Member" "Harmony Hill Shale Member" "Harrodsburg Limestone Member" "Hazel Green Member" "Hazelwood Member" "Hegeler Till Member" "Hely Member" "Hennepin Member" "Henry Formation" "Hermon Coal Member" "Herrin Coal Member" "Hillery Till Member" "Hoing Sandstone Member" "Holocene Series" "Hombergian Stage" "Houchin Creek Coal Member" "Howardton Limestone Member" "Hulick Till Member" "Hunton Limestone Megagroup" "Inglefield Sandstone Member" "Ironton Sandstone" "Isabel Sandstone Member" "Jamestown Coal Member" "Joachim Dolomite" "Joliet Formation" "Joppa Member" "Jordan Sandstone" "Jules Soil" "Kankakee Formation" "Karnak Limestone Member" "Kaskaskia Sequence" "Kellerville Till Member" "Kenwood Member" "Kenyon Member" "Keokuk Limestone" "Kerton Creek coal bed" "Kewanee Group" "Kewaunee Formation" "Kidd Member" "Kimmswick Subgroup" "Kinderhookian Series" "Kingdom Sandstone Member" "Kings Lake Formation" "Kinkaid Limestone" "Kiser Creek Member" "Knobs Megagroup" "Knox Dolomite Megagroup" "Kress Member" "La Salle Limestone Member" "Lacey Member" "Lacon Formation" "Lagonda Member" "Lake Creek Coal Member" "Lake Michigan Formation" "Lake Michigan Member" "Lawson Shale Member" "Lee Center Till Member" "Lemont Formation"