PAPERS OF GENERAL LNTEREST 29 



evidence that the streams bringing the sand had their 

 mouths toward the eastern side of the basin, the thicker 

 portions of the formations being nearer the source of supply 

 of the material. One of these formations, which has been 

 named the Waltersburg sandstone, is conspicuously de- 

 veloped in proximity to the Johnson-Pope County line but 

 thins to the east and the west, the lateral extent of the for-, 

 mation in an east west direction along the belt of outcrop, 

 as a conspicuous member of the section, being not greater 

 than forty miles. It is not improbable that this formation 

 may have accumulated as a delta deposit opposite the mouth 

 of a river entering the basin at this particular time in its 

 history. 



If the suggested interpretation of the succession of 

 Chester sandstones and limestone-shale formations of 

 southern Illinois is the correct one, then it would be ex- 

 pected that this same time interval would be represented by 

 more continuous limestone strata at a distance from the 

 shore line of the Illinois basin. The Chester Series is ex- 

 tensively represented in southeastern Tennessee and north- 

 eastern Alabama by a thick limestone formation which 

 probably represents the whole succession of limestone-shale 

 formations in southern Illinois. Only one thin sandstone 

 member has been recognized in southeastern Tennessee 

 which seems to occupy the position of the Hardinsburg 

 sandstone of the Ohio valley. A similar sandstone which 

 may be the same is present in the Alabama section. 



With the final withdrawal of the waters of the Chester 

 seas the Mississippian period came to an end and southern 

 Illinois became a portion of a widely stretching dry land 

 area, and remained in that condition for a long period of 

 time. This land surface was sculptured by the action of 

 streams which drained the area, and the whole surface 

 doubtless was covered with a strange vegetation, very dif- 

 ferent from that of the present time. No record of this 

 land life is preserved in our own state, but elsewhere sedi- 

 ments have been preserved, containing many fossil plants, 

 which were deposited during this dry land period in Illi- 

 nois. Finally a change in conditions was inaugurated, and 



