Page:EB1911 - Volume 27.djvu/655

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GEOLOGY]
UNITED STATES
631
Ordovician.
  Saluda bed 20 ±  ft. 
  Richmond formation   300 ±  ”
  Lorraine formation 300 ±  ”
  Eden (Utica) shale 250  ”
  Trenton limestone 130  ”


Iowa

  Glacial drift.
Unconformity.
Upper Cretaceous.
  Benton formation   0- 150  ft.
  Dakota formation  50- 100  ”
Unconformity.
Pennsylvanian.
  Missouri formation 1500  ft.
  Des Moines formation 250- 400  ”
Unconformity.
Mississippian.
  St Louis limestone 100  ft.
  Osage (Augusta) formation 200- 300  ”
  Kinderhook formation 150- 200  ”
Devonian.
  Lime Creek formation 80  ft.
  State Quarry beds  20-  40  ”
  Sweetland Creek shales  20-  40  ”
Unconformity.
  Cedar Valley limestone 250- 300  ft.
  Wapsipinicon formation (Independence, Fayette, Davenport) 100- 150  ”
Silurian.
  Anamosa limestone  50-  75  ft.
  Le Claire limestone 50  ”
  Delaware stage 200  ”
Unconformity.
Ordovician.
  Maquoketa shales 175  ft.
Possible Unconformity.
  Galena-Trenton limestone 290  ft.
  St Peters sandstone 100  ”
  Oneota formation (includes Shakopee, New Richmond and Oneota proper) 300  ”
Cambrian.
  St Croix sandstone ( = Potsdam) 1000  ft.
Unconformity.
Proterozoic.
  Sioux quartzite (?) 

This section is fairly representative for much of the central Mississippi Basin.


Oklahoma

Pennsylvanian.
   (Summit removed by erosion.)
  Seminole conglomerate 50  ft.
  Holdenville shale 260  ”
  Wewaka formation 700  ”
  Wetumka shale 120  ”
  Calvin sandstone  145- 240  ”
  Senora formation  140- 485  ”
  Stuart shale   90- 280  ”
  Thurman sandstone   80- 260  ”
  Boggy shale 2000-2600  ”
  Savannah sandstone  750-1100  ”
  McAlester shale 1150-1500  ”
  Hartshorne sandstone  150- 200  ”
  Atoka formation (Chickahoc chert lentil) 3200  ”
  Wapanucka limestone  100- 150  ”
Mississippian.
  Caney shale 1500  ft.
Devonian.
  Woodford chert 600  ft.
Silurian.
  Hunton limestone 160  ft
  Sylvan shale (upper part)   50- 100  ”
Ordovician.
  Sylvan shale (lower part) 250  ft.
  Viola limestone 750  ”
  Simpson series 1600  ”
  Arbuckle limestone 4000-6000  ”
Cambrian.
  Regan sandstone   50- 100  ft.
Unconformity.
Pre-Cambrian.
  Tishomingo granite (?) 

Composite section. The upper part is taken from vicinity of Coalgate, the lower part from the vicinity of Atoka.


West Central Colorado

Eocene or later.
  West Elk breccia 3000  ft.
Unconformity.
Cretaceous.
  Ruby formation 2500  ft.
Unconformity.
  Ohio formation (local only) 200  ft.
Unconformity.
  Laramie formation 2000  ft.
  Montana formation 2800  ”
  Niobrara formation 100- 200  ”
  Benton formation 150- 300  ”
  Dakota formation  40- 300  ”
Jurassic.
  Gunnison formation 350- 500  ft.
Unconformity.
Pennsylvanian.
  Maroon conglomerate 4500  ft.
Possible unconformity.
  Weber limestone 100- 550  ft.
Unconformity.
Mississippian.
  Leadville limestone 400- 525  ft.
Apparent unconformity.
Ordovician.
  Yule limestone 350- 450  ft.
Upper Cambrian.
  Sawatch quartzite  50- 350  ft.
Unconformity.
Archean.


The Bighorn Mountains of Wyoming

Cretaceous.
  De Smet formation (shale and sandstone) 4000  ft.
  Kingsbury conglomerate    0-1500  ”
  Piney formation (shale and sandstone) 2500  ”
  Parkman sandstone 350  ”
  Pierre shale 1500-3500  ”
  Colorado formation 1050-1700  ”
Comanchean.
  Cloverly formation (upper part may be Cretaceous)   30- 300  ft.
  Morrison formation (may be Jurassic)  100- 300  ”
Jurassic.
  Sundance formation  250- 350  ft.
Unconformity.
Triassic and Permian.
  Chugwater formation  750-1200  ft.
Pennsylvanian.
  Tensleep sandstone   30- 150  ft.
  Amsden sandstone  150- 350  ”
Mississippian.
  Madison limestone 1000  ft.
Unconformity.
Ordovician.
  Bighorn limestone 300  ft.
Unconformity.
Cambrian (Upper).
  Deadwood formation 900  ft.
Unconformity.
Pre-Cambrian.
  Granites.

This section is fairly representative for the Rocky Mountains.


Southern California

Quaternary.
  Alluvium, &c.
  Terrace deposits and dune sand.
Pliocene (?)
  Paso Robles formation 1000 +  ft.
Unconformity.
Miocene (?)
  Pismo formation (in south part of area) 3000 ±  ft.
  Santa Margarita (in north part of area) 1550 ±  ”
Unconformity.
Miocene.
  Monterey shale 5000-7000  ft.
  Vaquero sandstone    0- 500  ”
Unconformity.
Cretaceous.
  Atascadero formation 3000-4000  ft.
Unconformity.
Comanchean.
  Toro formation (Knoxville) 3000 ±  ft.
Unconformity.