DISTRIBUTION OF THE KEOKUK 67 



Waters," covering- a wide area, in Illinois, Indiana, Kentucky 

 and Tennessee. West of the river the most typical exposures 

 are in southeastern Iowa and northeastern Missouri. 



As exposed in the vicinity of the mouth of the Des Moines 

 river, the upper part of the Keokuk is composed of argilla- 

 ceous shales with limestone bands, while the lower portion con- 

 sists of heavily bedded, compact, bluish limestones. These 

 lithological characteristics, as well as its faunal peculiarities, 

 extend southwestward as far as the Sedalia anticlinal axis, 

 which, as has been previously stated, extends northwest and 

 southeast through Pettis, Marion and Camden counties. Along 

 this line the Lower Carboniferous rocks occur only in the cen- 

 tral part of the lirst mentioned county. The upper members 

 of the Ozark series are exposed everywhere in the southeast- 

 ern portion of Pettis, and extended northward in the shallow 

 creek beds to within a few miles of Sedalia. Directly upon 

 the old Magnesian limestone series rests the Chouteau, though 

 in places this is absent, and the Burlington limestone is the 

 uppermost rock exposed. At Sedalia the Chouteau limestone 

 is quarried at various places in the vicinity of the town. Usu- 

 ally a few feet of the very lowest bed of the Burlington are 

 exposed. West of Sedalia a few miles the Lower Coal Meas- 

 ures begin, and coal pockets are found in depressions of Chou- 

 teau limestone. It will be inferred from the foregoing that in 

 Pettis county the Lower Carboniferous is not represented 

 above the Lower Burlington. The higher members of this 

 series may have been removed through erosion during Carbon- 

 iferous times. Bat it is more probable that they were never 

 deposited here. It is a si gniii cant fact that down to the line of 

 the Sedalia axis, the Keokuk, in its typical lithological and 

 faunal development, is well defined. That southward, accord- 

 ing to those who have visited the southwestern part of the 

 State, all its characters are different. 



The presence of the Coal Measures in Pettis county is 

 manifestly an overlap, and the deposits contemporaneous with 

 the Keokuk may be represented beneath the Upper Carbon- 



