30 THE DEVONIAN OF MISSOURI. 



Thickness 



1. Compact, dirty-bluish-gray limestone bearing large Atrypa reticularis 



(Linnaeus) 2' 



2. Crystalline bluish-gray limestone, non-fossiliferous 2' 



3 and 4. Compact, very resistant light-bluish to pinkish gray limestone. 



"Weathers into rounded knobs with deep holes between. Carries Cranaena 

 iowensis (Calvin) and corals 15' 



5. Compact light-blue limestone, weathering to yellowish-brown. Bears many 



simple corals 1' 6* 



6. Light-gray compact fine-grained limestone bearing many small Atrypa 



reticularis (Linnaeus) 2' 6 * 



7. Compact dark-blue limestone weathering to yellow. Bears small A. reticu- 



laris (Linnaeus) in abundance 4' 



8. White to light-gray to dark-gray finely crystalline limestone, highly crinoidal 5' 



9. Grayish brown finely crystalline limestone; finer crystals than in 8 2' 



10. Dark-gray granular limestone bearing abundant large A. reticularis (Linna- 



eus) and many Stropheodonta demissa (Conrad) 2' 



11. White to light-gray coarsely crystalline limestone bearing large A. reticularis 



(Linnaeus) 1' 2 * 



12. LiKe number 10 2' 



Total thickness 39' 2 * 



In this section Chouteau lies unconformably on the Callaway 

 and the Callaway is unconformable on the Plattin. 



One mile east of last location the Devonian is 13 3^ feet 

 thick. The following is a section in Sec. 27, T. 47 N., R. 4 W. 



Unconformable Callaway-Chouteau Contact. , Feet. 



1. Crystalline, crinoidal limestone, darn: blue, coralline 3H 



2. Compact bluish-gray limestone bearing Acervularia davidsoni Edwards and 



Haime 1 



3. White, highly crinoidal limestone , 7 }4 



4. Mottled brownish crystalline limestone 1 



5. Light brown compact partly crystalline limestone H 



Unconformable contact with Plattin limestone. 



Two miles southeast of the above section no Devonian is 

 present but four miles south the Callaway is more than ten feet 

 thick. 



The Callaway pinches out to the east and is absent west of 

 Dry Fork of Charette Creek, excepting in sec. 8, T. 46 N., R. 

 2 W. where some float, identified as Callaway, occurs. Two 

 miles west of this place, in sections 12 and 13 of range 3, are 

 three Callaway outcrops, but the total thickness of the forma- 

 tion is not more than five feet. 



The Callaway occurs only in patches in Warren County 

 between Masses Creek and Charette Creek and it is not probable 

 that many patches will be found east of Charette Creek. Owing 

 to the variations in lithology and lack of fossils it is not always 

 possible to determine whether an outcrop is of Callaway or 

 Mineola. 



Exposures in Ralls County. — In northwestern Ralls County, 

 Sees. 10, 11, 14, 15, 20, 25, 26, 28, 29, 32 and 33, T. 56 N., R. 6 



