46 GEOLOaiCAL FORMATIONS 



I. Burlington Section. 



Feet. 

 10. Limestone, impure, somewhat clayey, thinly bedded, with chert 



nodules and seams 20 



9. Limestone, gray, coarse-grained, encrinital, with occasional clay 



partings and some flint 30 



8. Shales, bufl", calcareous and silicious, with thin limestone and 



flint bands 23 



7. Limestone, brown and gray, encrinital, compact and heavily 



bedded, with thin clay partings 27 



6. Limestone, rather soft, bufl, probably somewhat magnesian, ap- 

 parently sandy locally 6 



5. Oolite, gray 4 



4. Sandstone, soft, fine-grained, yellow, highly fossiliferous 6 



3. Limestone, gray, impure, fragmentary, with often an oolitic 



band below 9-13 



2. Sandstone, soft, fine-grained, bluish or yellowish, clayey, pass- 

 ing into sandy shales in places 20-30 



•1. Clay-shale, blue, fossiliferous, shown by borings to extend 50 to 



100 feet or more below the water level (exposed) 50 



All beds below No. 6 are regarded as Kinderhook. Nos. 

 7 and 8 are the lower Burlington limestone ; Nos. 9 and 10 the 

 upper Burlington limestone. 



II. Keokuk Exposures ; Tahorh Saw-mill. 



Feet. 



9. Drift and Loess 10 



8. Sandstone, soft, brown or yellowish, passing into a fine-grained 



conglomerate in places, irregularly cross-bedded, and lying 

 unconformably upon the next ( exposed ) 10 



7. Limestone, blue and ash-colored, brecciated, indistinctly bedded 



locally, and passing elsewhere into regularly bedded layers. . 25 



6. Limestone, brown, impure, arenaceous, heavily bedded 4 



5. Shale, blue, calcareous, clayey 10 



4. Limestone, impure, massive, weathering brown 7 



3. Clay-shale, with occasional limestone bands and abundant little 



crystal grottoes — the " geode-bed " 35 



2. Limestone, thinly bedded, somewhat shaly 5 



1, Limestone, blue, encrinital, heavily bedded, and more or less 



highly fossiliferous ( exposed ) 45 



Below ISTo. 4 of this section is the Keokuk group of Hall; 

 4 to 6, inclusive, form the Warsaw, of the same author ; while 

 No. 7 r^ the Saint Louis limestone reposing unconformably 

 upon the brown massive layer No. 6, and with the Coal Meas- 

 ures, No. 8, superimposed unconformably upon it. 



