PAPERS BY MEMBERS 125 



tirely covered, and in regions where the drift mantle is not 

 excessively thick the position of the formation can be de- 

 tected in the public highways, and frequently in the fields, 

 by the presence of the characteristic chert-like fragments in 

 the soil. In the valleys and the ravines the Yankeetown out- 

 crop is reduced to a mere line on the map, but upon some of 

 the divides it is the underlying rock over considerable areas 

 because of its resistant character, such being the case south- 

 east of New Design and east of Renault. Some excellent 

 and typical exposures of the formation may be seen in the 

 region about Yankeetown school, from which exposures- the 

 name of the formation has been derived. Northwest and 

 southwest of ]\Iillstadt. in the northern portion of the Water- 

 loo quadrangle, the Yankeetown constitutes the floor upon 

 which the Pennsylvanian beds have been laid down and it is 

 exposed in some of the stream beds which have been cut 

 through the Pennsylvanian. 



In its stratigraphic relations with the subjacent Renault 

 formation, the YankeetOAvn is believed to be unconformable, 

 although the unconformity can possibly not be established 

 with entire satisfaction. At different localities the higher 

 formation rests directly upon the very different beds of the 

 Renault, sometimes upon sandstone, sometimes upon lime- 

 stone and sometimes upon shale. Furthermore, the under- 

 lying Renault varies in thickness beneath the Yankeetown 

 from 40 feet or less to more than twice that thickness. If the 

 Yankeetown was not deposited unconformably upon the 

 Renault, there must have been an abrupt transition from the 

 remarkably heterogeneous conditions, as evidenced by the 

 variable, sediments of the Renault, to the wonderfully uni- 

 form sedimentation of the Yankeetown. 



4. Paint Creek Formation. 



General characters. The Paint Creek formation suc- 

 ceeds the Yankeetown with apparent conformity, and is very 

 uniform in its characteristics throughout the entire Randolph- 

 Monroe county area. Its thickness is from 60 to 80 feet, 

 the average thickness probably not much exceeding 60 feet. 

 The lower half of the formation, or perhaps somewhat more 

 than half, is almost entirely shale, while the higher portion 

 is largely limestone with shale partings. 



In the lower portion of the formation occurs one of the 

 most peculiar and most persistent beds in the whole Chester 

 group. It is a deep red, compact clay, without lamination or 

 bedding planes, commonly without inclusions of any sort, 

 but in at least one locality a number of irregularly rounded 

 pebbles of Chester limestone, from one or two to several 

 inches in diameter have been o1)served. The summit of this 



