"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"