FRUCTIFICATIONS FROM THE MAZON CREEK FLORA 



Location and Stratigraphy 



All specimens described in this study occur in ironstone (sideritic) nodules 

 from the Francis Creek Shale Member in the vicinity of Mazon Creek, Coal City, 

 or Wilmington in Will and Grundy Counties, Illinois (text fig. 1). These fossils 

 are generally referred to as the Mazon Creek flora. The Francis Creek Shale im- 

 mediately overlies the Colchester (No. 2) Coal at the base of the Carbondale For- 

 mation, Kewanee Group, Pennsylvanian. In American time-stratigraphic classifi- 

 cation, the Francis Creek Shale is in the middle part of the Desmoinesian Series; 

 it is in zone no. 10 of the floral zones of Read and Mamay (1964). In European 

 time stratigraphy this interval is probably in the Westphalian D (Jongmans, 1937; 

 Bode, 1958, 1960); however, the presence of some plants of Stephanian character 

 led Noe (1925, 1930, 1936) to place the interval in the Stephanian A. 



Materials and Methods 



The Mazon Creek fossils were deposited in rapidly accumulating mud. 

 Ironstone nodules formed around the fossil plants shortly after deposition. In 



vflk Strip mine spoil heaps 

 Outcrop of No. 2 Coal 

 Town 

 Locality 



5 10 Mi. 



lOKm. 



Text fig. 1 - Localities of the Mazon Creek flora in Grundy, Will, and Kankakee 

 Counties, Illinois. 1 - Mazon Creek proper (creek bed), locality 

 of all older collections. 2 - Spoil heaps where the Langford collection 

 was made. 3 - Pit 11, newest collecting locality; no material from 

 this locality has been used in this report. 



