THE MISSISSIPPIAN PERIOD 



599 



Fig. 426. Map showing the areas, in black, where the Mississippian system 

 appears at surface. The map also shows where the Mississippian system 

 is thought to exist, though buried (the lined areas), and the area from 

 which it is thought to have been removed by erosion (the dotted areas) . 

 By inference, also, the map shows the relations of land and water during 

 the Mississippian period. 



