558 



APPENDIX. 

 Generalized Section for Iowa. 1 



Names of Formations. 



Glacial drift. 

 -~ Unconformity -~~ 

 Benton formation. 



t-i o 



Thickness 

 in Feet. 



Characteristics. 



Shale, chalk, and thin-bedded limestone. 



Dakota formation. 

 ^ Unconformity ^~ 



Missouri formation. 



50-100 



1500 



Shales, sometimes calcareous; and sandstone, 

 sometimes concretionary. Thin hands of 

 lignite. Non-marine in part at least. 



Mainly light-colored, calcareous shales, grading 

 into pure limestone; limited amounts of bitu- 

 minous shales; few seams of coal of economic 

 importance. 



Des Moines formation, 



-^- Unconformity ^~ 

 St. Louis limestone. 100 



250-400 



Osage (Augusta) for- 

 mation. 



Clay-shales, often highly bituminous; sand- 

 stones, often in thick layers; limestones in 

 thin bands; important coal-beds. 



Light, ash-colored limestones, and marls, with 

 thin beds of sandstone. Good building stone. 



200-300 



Buff limestone and shales, underlain by coarse- 

 grained encrinital limestone; basal portion 

 usually ferruginous; prominent chert-beds. 



Kinderhook formation. 



150-200 



Bluish or greenish clay shales, fine-grained: 

 buff, compact, more or less argillaceous lime- 

 stones; sandstones. 



Lime Creek formation. 



80 



Dark-colored argillaceous shales, highly fos- 

 siliferous, and locally calcareous. 



State Quarry beds. 



Sweetland Creek shales. 

 -~"~- Unconformity-^^- 



Cedar Valley limestone 



20-40 



Light gray; good building-stone. Fish teeth. 



Black and greenish; Upper Devonian fossils. 



Pure to argillaceous limestone and dolomite: 

 sometimes massive, sometimes finely lami- 

 nated, frequently brecciated. 



Wapsipinicon forma- 

 t i o n . (Independ- 

 ence, Fayette, Dav- 

 enport.) 



100-150 



Carbonaceous shales with bands of impure con- 

 cretionary limestone; brecciated limestone. 



Anamosa limestone. 



50-75 



Soft, granular, evenly bedded dolomite; white 

 to buff and gray; important building-stone. 



x 



Le Claire limestone. 



50 



Massive or heavy-bedded highly crystalline 

 dolomite. Upper surface undulating; cross- 

 bedded on a large scale. 



Delaware stage. 

 -"v- Unconformity 



200 



Limestone containing large quantities of chert. 



Reports of Iowa Geol. Surv. 



