280 C. R. KEYES — CARBONIFEROUS STRATA OF CENTRAL IOWA. 



F. Bennington Sectio7i.—S. E. qr. N.W. qr. Sec. 9, T. 77 N., R. 21 W. 



7. Loss and stratified drift . . . . .47 feet. 



6. Yellow sandstone, thinly bedded . . . . 20 " 



5. Blue sandstone, with a layer of white clay . . I2 " 



4. Bituminous shale, with a compact, nodular and highly fer- 



ruginous band . . . . . . 6 " 



3. Coal . . . . . . . 2 " 



2. Drab fire-clay . . . . . . 3 " 



1. Sandy shales (exposed) . . . . . 5 " 



VL Ford Bluff.— K E. qr. S. E. qr. Sec. 10, T. 77 N., E. 22 W. 



9. Drift and loss . . . . . .10 feet. 



8. Light-yellow sandstone, soft, heavily bedded above, thinly 



bedded below, with much clay . . . .35 *' 



7. Dark shale, highly bituminous in places, with hard concre- 



tionary layer 



6. Fire-clay with sigillarid roots 



5. Drab shales, somewhat sandy above 



4. White clay 



3. Soft sandstone, buff, heavily bedded 



2. White clay 



2 



12 

 3 

 4 

 4 



1. Sandy and clayey shales (exposed to water level) . 25 " 



VII. Des Moines Section. — (^Several Exposures in the City of Des 3Ioi)ies.) 



17. Variegated clayey shales . . . . .15 feet. 



16. Blue earthy limestone, nodular and weathering brown ; 

 contains Productus muricatus,^. and P.; Chonetes verneui- 

 lianus, N. and P.; and Streptorhynchus crenistriatum, 



Phillips . . . . . . . t " 



15. Variegated clayey shales . . . . . 8 " 



14. Bituminous shales, with concretionary masses below which 

 contain Productus muricatus, N. and P. ; P. cora, d'Orb. ; 



etc. A thin coaly seam shown in some places . . 3 " 



13. Light-colored shales, clayey, drab and yellow . . 7 '' 



12. Variegated clay-shales . . . . . 4 " 



11. Nodular limestone, earthy throughout, highly fossiliferous 2 " 



10. Light-colored and variegated shales . . . 5 " 



9. Impure limestone, somewhat fossiliferous . . . 1 " 



8. Light-colored clays . . . . . 5 " 



7. Buff-colored micaceous sandstone, concretionary in places 



and passing into sandy shales elsewhere . . 15 to 25 '* 



6. Light-colored shales, sandy in places . . . 4 " 



5. Coal, impure 



4. Light and dark sandy shales 



3. Bituminous shales, highly fossiliferous 



2. Coal, rather impure 



1. Fire-clay (exposed to water level) . 



2 

 20 



2 

 2 

 1 



