4o6 STUART WELLER 



than the Menard. In Randolph and Jackson counties no notable 

 shale members have been recognized in the formation, and no 

 conspicuous chert layers have been seen in place, although in some 

 localities the residuum from the formation shows a considerable 

 amount of broken chert. 



In the southern counties the Kinkaid limestone is similar in 

 character to the exposures in Jackson County; this is especially 

 true in Union County, but as the formation is traced to the east 

 it is found to include important shale beds and some very notable 

 chert horizons. A very characteristic shale bed in the Kinkaid in 

 Johnson and Pope counties, and perhaps also in Hardin, near the 

 base of the formation and some eight or ten feet thick, is a dark- 

 red color. There are perhaps other red-shale horizons in the for- 

 mation. Other shale beds are of a distinctly olive-green color, and 

 these red and green shales are a very characteristic feature of the 

 formation in the more eastern portion of its extent. In this same 

 region there are one or more remarkable chert horizons in the , 

 Kinaid. The more important of these is a massive bed three or 

 more feet thick, commonly rather light colored, and in places with 

 a slightly greenish tint. The resistant character of this chert 

 makes it a conspicuous feature in places in the residuuni from the 

 formation as seen along roadsides, in stream beds, and on hill- 

 sides. In places sub cubical masses of the chert a foot or more in 

 dimension are strewn over the surface where the bed is present. 

 There are other less conspicuous chert beds, some of them dark 

 colored and similar in character to the chert that is so abundant in 

 the Vienna limestone. The limestone layers of the Kinkaid in this 

 more eastern region are quite similar in Hthologic character to the 

 beds in Randolph and Jackson counties. 



The thickness of the Kinkaid limestone exhibits considerable 

 variation due to the fact that it is the highest formation of the 

 Chester series, and has consequently been subjected to the pre- 

 Pennsylvanian erosion. Its greatest thickness in Jackson County is 

 in excess of fifty feet, and it may vary from this maximum thick- 

 ness to nothing at all, for in places the Pennsylvanian strata rest 

 upon the Degonia sandstone. In the southern counties the - 

 formation is also variable in thickness, but on the whole it is notably 



