IOWA ACADEMY OF SCIENCES. 



Holomite, light gray 



Limestone, light gray, with some chert Hnd saud. 



Drillings wastied away 



Sand, clean, white 



Dolomite, yellowish, sandy 



Drillings washed away 



Limestone, dark gray, do'omitic. 



Limestone, dark gray, nearly pure 



Limestone, dark gray, arenaceous 



Dolomite, dark gray, aren«ceous 



Dolomite, rusty gray, with sand and shale 



Dolomite, rusty gray, mixed with pure llmestnnp. 

 Dolomite, rusty gray, with much pure limestone. . 



Limestone, dark gray, with some little sand 



Limestone, mixed witb sand and shale 



Limestone, brownish gray, with much sand 



Sand, light gray, with some lime 



Sand, light gray, dolomitic 



Sand, white, fine grained 



Sand, rustv. coarser grained 



Drillings WHshed awHy 



Sandstone, very hard {li hours in uri ling 5 feet), mnuy ninki«-h grains 

 resembling quartzite; mixed with much sba.e and dolomite from 

 above 



Same as No. 4, but with some little slate 



Slate, very dark, compact 



Slate, same as No. 2, but harder 



Drill sto pued in pure slate , at 2, 430 feet. 



SUMMARY. 



a 

 z 



66 



64 65 



62-63 



59-61 



55-58 



50-54 



48-49 



45-47 



FORMATION. 



Pleistocene 



Augusta— Uppfr Burlington 

 Augusta— Lower Burlington 



Kinderhook 



Devonian 



Silurian 



Maquoketa 



Trenton 



