UPPER KINKAID (MISSISSIPPIAN) MICROFAUNA 

 FROM JOHNSON COUNTY, ILLINOIS 



CHALMER L. COOPER 

 U. S. Geological Survey 



Abstract — In northwestern Johnson County, Illinois, the Wayside formation 

 (Lower Pennsylvanian) rests with apparently slight disconformity upon the Kinkaid 

 formation (upper Chester). An important and varied microfauna, consisting of 

 Foraminifera, ostracodes, and conodonts is described and compared with Morrow 

 microfaunas from the Midcontinent and other areas. The Foraminifera include the 

 genera Endothyra, Glomospira, Hyperammina, Palaeotextularia, Trepeilopsis, and 

 Millerella. The last is specifically described from the Mississippian for the first 

 time. Five genera of conodonts and 20 genera (35 species) of ostracodes are included 

 in the fauna. 



THIS paper presents the microfauna from 

 beds that are thought to be the youngest 

 Chester in the area regarded as the type for 

 the Mississippian system, where these beds 

 could be examined and studied in relation to 

 the superjacent Pennsylvanian. The type 

 area for the Kinkaid formation is located 

 along Kinkaid Creek, which cuts through 

 the formation in NW. £ sec. 6, T. 8 S., R. 

 4 W., Jackson County, Illinois. This is less 

 than 15 miles southeast of the town of 

 Chester and the locality from which the 

 fauna in question was collected is about 40 

 miles southeast of Chester. All known out- 

 crops of the Kinkaid in southern Illinois 

 that might show the contact with the over- 

 lying Pennsylvanian were visited in order 

 to obtain as much data as possible on the 

 contact relations of the Pennsylvanian- 

 Mississippian boundary. The best section 

 observed is that exposed on a north tribu- 

 tary of Lick Creek, which flows southeast 

 across sec. 31, T. 11 S., R. 2 E., crossing the 



upper Kinkaid boundary in the northwest 

 quarter of the section. This outcrop was 

 described in detail by Lamar (1925, p. 80) 

 who measured about 30 feet of Pottsville 

 (Wayside) overlying 91 feet of the Kinkaid 

 formation, the latter containing about one- 

 third shale and two-thirds limestone. The 

 details of the contact relations, modified 

 somewhat from Lamar's subdivisions, are 

 shown in figure 1. 



A coral fauna from these beds was de- 

 scribed by Easton (1945) who correlates 

 the Kinkaid beds containing Kinkadia 

 trigonalis, Triplophyllites palmatus, and 

 Caninostrotion variabilis with the upper part 

 of the Pitkin formation of western Arkansas. 

 These corals were obtained from the mas- 

 sive limestone at the base of the section 

 (fig. 1) and the thin limestones a short 

 distance above it (between samples 2 and 

 5). Concerning the coral fauna he concluded 

 (p. 384): 

 . . . the geographic distribution of the corals 



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