SECTIONS IN IOWA. 285 



relations according to the present understanding can be pointed out in 

 the briefest possible manner. These sections are taken at places where 

 the must minute and satisfactory information is to be obtained, and they 

 assume their names from these localities. They are all marked on th i 

 general section. 



The Burlington Section. 



Feet. 



10. Impure and often somewhat clayey thinly bedded limestone with chert 



nodules and seams 20 



'.>. Gray, coarse grained encrinital limestone with occasional clay partings 



and some flint : '° 



s. butf calcareous and siliceous shales with thin limestone ami Hint bands. . 23 

 7. Brown and gray encrinital limestone, compact and heavily bedded, with 



thin clay partings 27 



Ik Rather soft buff limestone, probably somewhat magnesian, apparently 



sandy locally ' 



5. Gray oolite -± 



4. Soft, fine grained, yellow sandstone, highly fossiliferous 6 



:;. Gray, impure limestone, fragmentary, with often an oolitic band below. . 9-1:: 

 2. Soft, line grained bluish or yellowish clayey sandstone passing into sandy 



shales in places , ■ : 20-30 



1. Blue clay-shale, fossiliferous, shown by borings to extend -30 to 100 feet 



or more below the water level ; exposed 50 



All beds below number G are regarded as Kinderhook. Numbers 7 and 

 S form the lower Burlington limestone; numbers '.land 10 the upper 

 Burlington limestone. 



Keokuk Exposures: Tabor's Saw-mill. 



Feet. 



'.). Drift and loess 1( > 



s. Soft brown or yellowish sandstone passing into a finegrained conglomer- 

 ate in places, irregularly cross-bedded and lying un conformably upon 



the next ; exposed ht 



7. Blue and ash-colored breccia led limestone, indistinctly bedded locally and 



passing elsewhere into regularly bedded layers 25 



<;. Brown, impure arenaceous limestone, heavily bedded 4 



."). Blue, calcareous clayey shale 1° 



4. Impure limestone, massive and weathering brown < 



:;. ( lav-shales with occasional limestone bands and abundant little crystal 



grottoes — the "geode-bed" 35 



2. Thinly bedded somew hat shaly limestone 5 



1. Blue encrinital limestone, heavily be, Med and more or less highly fossil- 

 iferous ; exposed '•' 



Below number I of this section is the Keokuk group of Hall: 1 to 6, 

 inclusive, form the Warsaw of the same author : while number 7 is the St. 



