SPORE DISTRIIH'TION — CARBONDALE 



91 



marked contrast to the other samples of 

 Colchester (No. 2) Coal. None of the spe- 

 cies of Triletes in macerations 824-826 nor 

 Calamospora is represented. In contrast to 

 all other samples of the Colchester (No. 2) 

 Coal, T. augustac and Spencerisporites cf. 

 S. gracilis are found in maceration 580. 



The fourth sample of this coal (macera- 

 tion 567) , from LaSalle County, contains 

 no mega spores. 



Two samples, questionably of the Col- 

 chester (No. 2) Coal, from rotary drill 

 samples, Hamilton County, were examined. 

 One (maceration 581), probably is a coal 

 of Tradewater age, in that Triletes ramosus 

 with adhering spores of Densosporites was 

 identified. The other (maceration 582) 

 contains some of the more common spores 

 found in the Colchester (No. 2) Coal. 



All of the genera and species represented 

 in the Colchester (No. 2) Coal occur in 

 some of the underlying coals of the Trade- 

 water Group. Although the assemblages 

 from different localities vary considerably, 

 they appear to differ from those of the 

 upper part of the Tradewater Group by 

 1) a lower incidence of Parasporites and 

 Spencerisporites, 2) greater relative abun- 

 dance of Cystosporites, and 3) fewer spores 

 of Triletes triangulatus. All the samples 

 are distinguishable from the Summum 

 (No. 4) Coal and the overlying coals of 

 the Carbondale Group by the greater rela- 

 tive abundance of Cystosporites and the ab- 

 sence of T. glabratns (text fig. 9) . C. verru- 

 cosus is represented in the Indiana Coal IV 

 but is not known to occur in any younger 

 coal. 



Indiana Coal IV 



The Indiana Coal IV is geographically 

 restricted to an area centering in Greene 

 County, Indiana (Wanless, 1955) . It is 

 known to extend into parts of Edgar, Clark, 

 Crawford, and Lawrence Counties of Illi- 

 nois. This coal occurs between the Col- 

 chester (No. 2) and the Summum (No. 4) 

 Coals of Illinois. 



The Indiana Coal IV is split in a dia- 

 mond drill core from Edgar County, Illi- 

 nois. The thinner (8-inch) lower coal of 

 the split (maceration 881) is dominated by 

 spores of Triletes rugosus (80 percent) . 



Monoletes, Cystosporites varius, C. gigan- 

 teus, and C. verrucosus also were well rep- 

 resented. The assemblage from this coal is 

 similar in content to that of several sam 

 pies of the Colchester (No. 2) and in the 

 relative abundance of Cystosporites, T. ru- 

 gosus, and Monoletes. In this core the In- 

 diana Coal IV is distinct from the overly- 

 ing No. 5 and Grape Creek (No. 6) Coals, 

 which contain numerous spores of T. glab- 

 ratns but lack those of Cystosporites. 



Summum (No. 4) Coal 



Summum (No. 4) Coal is extensive in 

 southern Illinois, although commonly only 

 a few inches thick. Its equivalent, Indiana 

 IVa, locally attains a thickness of from 1 to 

 2 feet in Indiana. This coal, like the Rock 

 Island (No. 1) Coal in western Illinois 

 (Cady, 1952), is lenticular. 



The following genera and species were 

 identified from one sample of the Summum 

 (No. 4) Coal (maceration 463) , Jersey 

 County: 



Triletes triangulatus 



(A) 



T. glabratns 



(C) 



T. augustae 



(C) 



T. mamillarius 



(P) 



Calamospora cf. C. laevigata 



fp) 



Monoletes 



(R) 



This assemblage is distinct from those of 

 most samples of the Colchester (No. 2) , 

 No. 5, Briar Hill (No. 5a) , and Herrin 



(No. 6) Coals, in its lack of Cystosporites, 

 Triletes rugosus, and the relative rarity of 

 Monoletes. T. glabratns is abundant for 

 the first time in the Pennsylvanian of Illi- 

 nois. The only previous occurrence was the 

 few spores found in the "Makanda" Coals 

 of the Caseyville Group. Although Lyco- 

 spora is dominant among the small spores 



(Kosanke, 1950) , none of the megaspores 

 known to be botanically related to Lyco- 

 spora are present in this sample of the 

 Summum (No. 4) Coal. 



No. 5 Coals 



The No. 5 Coal of Illinois, called Har- 

 risburg (No. 5) in southern Illinois and 

 Springfield (No. 5) in central, western, and 

 northern Illinois, is second to Herrin (No. 

 6) Coal in commercial importance in 

 Illinois. 



