OHIO 

Permian . Dunkard formation . . . Pennsylvanian . Monongahela formation .. Conemaugh formation . . Alleghany formation . . . Pottsville conglomerate .. Unconformity . Mississippian . Maxville limestone .

. . Waverley

series Logan group . . . . Black Hand conglomerate . Cuyahoga shale . . . . Sunbury shale . . . . Berea grit . . . . Bedford shale . . .

. Devonian . Ohio shale . . . . Olentangy shale . . . .

Delaware limestone . . . Columbus limestone . . . Silurian . Monroe formation . . .

Niagara group . . . . Clinton limestone . . Medina shales (?) . . . (Belfast bed.) Conway schist Amherst schist }5000 Brinfield fibrolite-schist Goshen schist 2000 Unconformity . Ordovician . Hawley schist 2000 ft . (?) Devonian . Bernardston series .. Unconformity . Silurian .

Leyden argillite 300 ft . 1950 ft . (?) „ (?) ?) (?) (?) Canaan formation Greenbrier limestone Pocono sandstone Devonian . Hampshire formation Jennings formation Romney shale Unconformity . Monterey sandstone Silurian . Lewiston limestone Rockwood formation Cacapon sandstone Tuscarora quartzite Juniata formation Ordovician . Martinsburg shale Middle and Upper Cambrian . Pugh formation Pickens sandstone Unconformity . Mississippian . Braxton formation Upshur sandstone . . 700 ft . . .

300– 500 „ . . 300–450 ,, . . 400–5O0 „ . . I000–1300 ft . . . 350– 400 „ . . 70– 90 „ . . 1500–1800 ft . 3000–3800 „ . . 1000–1300 „ . . go– 200 ft . . .

550–1050 ft . . . Loo– 800 „ . . 100– 63o „ . . 30– 300 . . 205–1250 . . 800–1800 ft . . . . . C . 25 ft . . .

. . 200– 250 ft . . . . . 400– 500 „ . . . . 165– 300 . . . . 250 „ . . C . 25 ft . . .

. . Pao– 150 ft . . . . .. 50— 500 „ . . . . 150– 300 „ . . . . 5– 30 ,, . . . . 5– 195 „ . . .

. 50– 150 „ . . . . 300–2600 ft . . . . . .20– 35 . . . . 30– 40 „ . . . .

Ito ,, . . . . 50– 600 ft .

. . . . 150– 350 „ . . . 10– 50 „ . . . . 50– 150 „ Ordovician . Saluda beds 2o= ft .

Richmond formation 300 * „ Lorraine formation 300* „ Eden (Utica) shale 250 Trenton limestone 130 IOWA Glacial drift . Unconformity . Upper Cretaceous . Benton formation o- 150 ft .

Dakota formation 50- too „ Unconformity . Pennsylvanian .

Missouri formation 1500 it . Des Moines formation 250- 400 „ Unconformity . Mississippian . St Louis limestone too ft . Osage (Augusta) formation 200- 300 „ Kinderhook formation 150- 200 „ Devonian . Lime Creek formation State Quarry beds 20- Sweetland Creek shales 20-Unconformity . Cedar Valley limestone 250- 300 ft . Wapsipinicon formation (Independence, Fayette, Davenport) too- 15o „ Silurian . Anamosa limestone 50- 75 ft . Le Claire limestone 5o „ Delaware stage 200 „ Unconformity .

Ordovician . Maquoketa shales 175 ft . Possible Unconformity .

Galena-Trenton limestone 290 ft . St Peters sandstone too „ Oneota formation (includes Shakopee, New Richmond and Oneota proper) 300 „ Cambrian . St Croix sandstone (= Potsdam) . Unconformity . Proterozoic . Sioux quartzite . . . . (?) This section is fairly representative for much of the central Mississippi Basin . OKLAHOMA Pennsylvanian .

(

Summit removed by erosion.) Seminole conglomerate 5o ft . Holdenville shale 26o „ Wewaka formation 700 „ Wetumka shale 120 „ Calvin sandstone 145- 240 „ Senora formation 140- 485 „ Stuart shale 90- 280 „ Thurman sandstone 8o- 26o „ Boggy shale 2000-2600 „ Savannah sandstone 750-1100 „ McAlester shale 1150-1500 „ Hartshorne sandstone 150- 200 „ Atoka formation (Chickahoc chert lentil) . 3200 „ Wapanucka limestone too- 15o „ Mississippian . Caney shale 1500 ft . Devonian . Woodford chert 600 ft . Silurian . Hunton limestone 16o ft . Sylvan shale (upper part) 50- too „ Ordovician . Sylvan shale (lower part) 250 ft . Viola limestone 750 ,, Simpson series 1600 „ Arbuckle limestone 4000--6000 „ Cambrian . Regan sandstone -- 50- Too ft .

Unconformity . Pre-Cambrian . Tishomingo

granite . . . (?) Composite section . The upper part is taken from vicinty of Coalgate, the lower part from the vicinity of Atoka .