| Guruh yoki shakllanish | Davr | Izohlar |
|---|
| Altamont shakllanishi | Karbonli | |
| Tuxmatni shakllantirish | Siluriya | |
| Brainardning shakllanishi | Ordovik | |
| Bronson guruhi/Dennis Formation | Karbonli | |
| Burlington ohaktoshi | Karbonli | |
| Sidar vodiysi guruhi/Coralville shakllanishi | Devoniy | |
| Sidar vodiysi guruhi /Linwood shakllanishi | Devoniy | |
| Sidar vodiysi guruhi /Litograf shahar shakllanishi | Devoniy | |
| Sidar vodiysi guruhi /Kichkina sadr shakllanishi | Devoniy | |
| Sidar vodiysi guruhi /Shell qoyalarining shakllanishi | Devoniy | |
| Chapin shakllanishi | Karbonli | |
| Cherokee guruhi | Karbonli | |
| Coralville shakllanishi | Devoniy | |
| Dakota shakllanishi | Bo'r | |
| Decorah slanetsi | Ordovik | |
| Dennis Formation | Karbonli | |
| Devining shakllanishi | Karbonli | |
| Dunleith Formation | Ordovik | |
| Ingliz daryosi shakllanishi | Karbonli | |
| Galena Dolomit | Ordovik | |
| Galena guruhi/Cummingsville shakllanishi | Ordovik | |
| Galena guruhi /Decorah slanetsi | Ordovik | |
| Galena guruhi /Dubuque Formation | Ordovik | |
| Galena guruhi /Dunleith Formation | Ordovik | |
| Galena guruhi /Guttenberg shakllanishi | Ordovik | |
| Galena guruhi /Ion hosil bo'lishi | Ordovik | |
| Galena guruhi /Spechts feribotining shakllanishi | Ordovik | |
| Galena guruhi /Aqlli ko'l shakllanishi | Ordovik | |
| Gilmore Siti ohaktoshi | Karbonli | |
| Glenwood shakllanishi | Ordovik | |
| Gower Formation | Siluriya | |
| Katta aylanma yo'l | Ordovik | |
| Graneros slanets | Bo'r | |
| Guttenberg shakllanishi | Ordovik | |
| Hackberry Group/Lime Creek shakllanishi | Devoniy | |
| Xempton shakllanishi | Karbonli | |
| Xopkinton Dolomit | Siluriya | |
| Mustaqillik slanetsi | Devoniy | |
| Iola shakllanishi | Karbonli | |
| Ion hosil bo'lishi | Ordovik | |
| Kanzas Siti guruhi/Swope shakllanishi | Karbonli | |
| Keokuk ohaktoshi | Karbonli | |
| LaPorte City Formation | Siluriya | |
| Lekompton shakllanishi | Karbonli | |
| Lime Creek shakllanishi | Devoniy | |
| Yo'qotilgan filial shakllanishi | Karbonli | |
| Maquoketa guruhi | Ordovik | |
| Maquoketa guruhi /Brainard slanetsi | Ordovik | |
| Maquoketa guruhi /Fort Atkinson ohaktoshi | Ordovik | |
| Maquoketa guruhi /Neda shakllanishi | Ordovik | |
| Maquoketa guruhi /Tarozi slanets | Ordovik | |
| Marmaton guruhi/Labet | Karbonli | |
| Maynes Creek shakllanishi | Karbonli | |
| Makkreni ohaktoshi | Karbonli | |
| Mifflin shakllanishi | Ordovik | |
| Mosalem shakllanishi | Siluriya | |
| Nachusaning shakllanishi | Ordovik | |
| Shimoliy tepaliklar guruhi/Ingliz daryosi | Devoniy | |
| Oneota Formation | Ordovik | |
| Pawnee shakllanishi | Karbonli | |
| Pekatonika shakllanishi | Ordovik | |
| Pella shakllanishi | Karbonli | |
| Plattevil guruhi/Katta aylanma yo'l | Ordovik | |
| Plattevil guruhi /Mifflin shakllanishi | Ordovik | |
| Plattevil guruhi /Pekatonika shakllanishi | Ordovik | |
| Plattevil guruhi /Quimbys Mill Formation | Ordovik | |
| Prosser ohaktoshi | Ordovik | |
| Quimbys Mill Formation | Ordovik | |
| Racin shakllanishi | Siluriya | |
| Shanba kuni tog 'shakllanishi | Ordovik | |
| Scotch Grove Formation | Siluriya | |
| Shawnee guruhi/Deer Creek ohaktoshi | Karbonli | |
| Shawnee Group /Kanvaka shakllanishi | Karbonli | |
| Shawnee Group /Oq ohaktosh | Karbonli | |
| Shell qoyalarining shakllanishi | Devoniy | |
| Spechts feribotining shakllanishi | Ordovik | |
| Spillville Formation | Devoniy | |
| Sent-Luis shakllanishi | Karbonli | |
| Avliyo Piter Qumtoshi | Ordovik | |
| Stanton Formation | Karbonli | |
| Styuartvillning shakllanishi | Ordovik | |
| Swope shakllanishi | Karbonli | |
| Traverse Group/Sidar vodiysining shakllanishi | Devoniy | |
| Wapsipinicon shakllanishi | Devoniy | |
| Varshava formasiyasi | Karbonli | |
| Vassonvillning shakllanishi | Karbonli | |
| Aqlli ko'l shakllanishi | Ordovik | |
| Sariq buloqlar guruhi/Sheffildning shakllanishi | Devoniy | |
