92 



ILLINOIS STATE GEOLOGICAL SURVEY 



The following genera and species were 

 identified from the Springfield (No. 5) 

 Coal (maceration 630) , Sangamon County: 

 Monoletes (A) 



Triletes glabratus (P) 



T. triangulatus (P) 



Cystosporites varius (P) 



T. auritus (R) 



T. rugosus (R) 



T. mamillarius (R) 



Spencerisporites cf. S. gracilis (R) 



Calamospora cf. C. laevigata (R) 



This sample and another (maceration 

 583) from Wabash County differ from the 

 Summum (No. 4) Coal in that T. rugosus 

 and Cystosporites are present. Three sam- 

 ples of the No. 5 Coal contained fairly 

 abundant spores of T. glabratus. This spe- 

 cies is also noted in two other samples of 

 the No. 5 Coal (macerations 422C and 

 569D, not listed in table 2) . 



A diamond drill core sample of No. 5 

 Coal (macerations 880 and 879) from Ed- 

 gar County did not contain any spores of 

 Cystosporites or Triletes rugosus and was 

 similar to the sample of Summum (No. 4) 

 Coal in this respect. It did, however, con- 

 tain fairly abundant spores of T. glabratus 

 and representatives of both Spencerisporites 

 and Parasporites. 



Briar Hill (No. 5a) Coal 



Briar Hill (No. 5a) Coal is generally re- 

 stricted to the southeastern part of the Illi- 

 nois Basin and is rarely mined. 



The following genera and species were 

 identified from the Briar Hill (No. 5a) 

 Coal (maceration 633A-B) from the gen- 

 eral area of its type section in Gallatin 

 County, where it is 2 feet thick. 



Monoletes (A, A) 



Triletes rugosus (A, C) 



Cystosporites giganteus (A, - ) 



C. varius (A, - ) 



T. triangulatus (P, P) 



Calamospora cf. C. laevigata (C, - ) 



Spencerisporites cf. C. gracilis (P, - ) 



Cystosporites breretonensis ( -, R) 



T. glabratus ( -, R) 



This assemblage differs from those of 

 the No. 5 Coal in the rarity of spores of 

 Triletes glabratus, and in the more abun- 

 dant occurrence of spores of T. rugosus and 

 Cystosporites. Only Calamospora and T. 

 rugosus have been identified from one other 



sample of Briar Hill (No. 5a) Coal (macer- 

 ation 507 A-B, not listed in table 2) . 



Herrin (No. 6) Coal 



The Herrin (No. 6) Coal is the princi- 

 pal commercial coal of Illinois. It may at- 

 tain a maximum thickness of 14 feet or 

 more. The extensive study by Schopf 

 (1938) of the megaspores of this coal is 

 well known. His results have been incor- 

 porated into the distribution chart (text 

 fig. 9) . The dominant elements appear to 

 be Triletes glabratus, T. rugosus, Mono- 

 letes, T. triangulatus, T. mamillarius, and 

 Cystosporites. 



A sample (maceration 878) of Grape 

 Creek (No. 6) Coal from Edgar County 

 contained very abundant spores of Triletes 

 glabratus, but none of Cystosporites. 



Apparently Spencerisporites, found in 

 two samples of the No. 5 Coal and in one 

 of the Briar Hill (No. 5a) and one of the 

 Colchester (No. 2) Coals, is not represented 

 in the Herrin (No. 6) Coal. The larger 

 spores of Calamospora, noted in several 

 samples of the No. 2 Coal, the Summum 

 (No. 4) Coal, and in one sample of both 

 the No. 5 and No. 5a Coals, also are miss- 

 ing. 



Parasporites is common for the first time 

 since its occurrence in an unnamed coal 

 above the DeKoven Coal of the Tradewater 

 Group, although scattered occurrences are 

 noted in the No. 2 and No. 5 Coals. 



Summary 



The coals of the Carbondale Group, 

 above the Colchester (No. 2) Coal and the 

 Indiana Coal IV, are distinguished from 

 older coals by a fairly abundant occurrence 

 of both the spinose and smooth aphanozo- 

 nate megaspores. Spores of Triletes gla- 

 bratus first occur in "Makanda" Coals of 

 the Caseyville Group, are absent from coals 

 of the Tradewater Group and from Col- 

 chester (No. 2) Coal and Indiana Coal IV, 

 but reoccur, at many places in great abun- 

 dance, in the younger coals of the Carbon- 

 dale Group. Spores typical of T. auritus 

 are not as common in the Carbondale coals 

 as they are in some of the Tradewater coals. 

 Spores of the section Zonales of Triletes 

 apparently are not represented in the Car- 

 bondale and younger coals. 



