634 STUART WELLER 



At a distance from the Ozark region, the Chouteau fauna is recog- 

 nized in the Goniatite Limestone of Rockford, Indiana, where the 

 Cephalopod genus Prodromites occurs, the further distribution of this 

 genus being in the Chouteau Limestone of Pettis County, Missouri, 

 and in the higher beds at Burlington. In certain portions of the 

 Waverly of Ohio, Kentucky, and Indiana characteristic elements of 

 the same fauna may be recognized. In still another direction this 

 fauna occurs in the limestones of the higher portion of the Kinder- 

 hook beds in Marshall County, Iowa, and in the Wassonville lime- 

 stone of Washington County, Iowa. 



From a detailed consideration, therefore, it is seen that the Kinder- 

 hook strata of the Mississippi Valley region contain two distinct 

 faunal assemblages, each of which shows modifications into various 

 facies. During earlier Kinderhook time these two faunas were 

 restricted, one to the more northern, the other to the more southern 

 region, and the two Kinderhook provinces were separated by some 

 barrier, doubtless a land barrier. Near the close of the Kinderhook 

 epoch, the barrier separating the two provinces was removed, and the 

 fauna from the south migrated into the northern province. The 

 northern fauna, however, probably continued to live in a more and 

 more restricted area to the close of Kinderhook time, since at Kinder- 

 hook, Illinois, there is apparently no evidence of the presence of the 

 southern fauna in any beds between those bearing the typical northern 

 Kinderhook fauna and the base of the Burlington limestone. With 

 the removal of the barrier, however, the northern fauna did not make 

 any headway into the southern province. 



