94 



ILLINOIS STATE GEOLOGICAL SURVEY 



cause many of their older coals are of com- 

 mercial importance. 



Schemel (1950a) reported the occurrence 

 of spores of Triletes agninus (Zerndt) , 

 Schopf, Wilson, and Bentall and a single 

 specimen referred to T. radiatus Zerndt 

 (T. radiosus Schopf, Wilson, and Bentall) 

 from a coal of Chester or Springer age in 

 Utah. Zerndt (1937a) originally described 

 spores of these species and of T. splendidus 

 (Zerndt) Schopf, Wilson, and Bentall from 

 the Dinantian and Namurian A of the Up- 

 per Silesian Coal Basin of Poland. All 

 three species have about the same strati- 

 graphic range in this basin. Although a few 

 spores of T. splendidus were found in the 

 uppermost Chester sample examined, nei- 

 ther of the two species reported by Schemel 

 (1950a) was represented. 



Chaloner (1954b) described megaspores 

 of probable Osage or Kinderhook age and 

 some from the Beaver Bend Limestone in 

 the lower part of the Chester Series in Indi- 

 ana. Spores reported from the Beaver Bend 

 Limestone are those of Triletes subpilosus 

 forma major, T. indianensis, T. echinoides, 

 T. paleocristatus (Chaloner, 1956b) , and 

 Cystosporites giganteus. All except the 

 latter two species of Triletes were repre- 

 sented in the coal in the Bethel (Moore- 

 town) Formation of Kentucky, and T. ech- 

 inoides was noted, as occurring sporadi- 

 cally, higher in the section. No specimens 

 of T. paleocristatus were seen during this 

 investigation. Only spores of T. indianen- 

 sis seem to be restricted to the lower part 

 of the Chester; Didymosporites is appar- 

 ently abundantly represented only in the 

 lower part of the Chester; spores of both T. 

 subpilosus forma major and C. giganteus 

 occur, at some places abundantly, through- 

 out the Chester, the latter species alone ex- 

 tending up into Pennsylvanian rocks. 

 Spores other than those described by Chal- 

 oner also were found; several of them, or of 

 closely related forms, occur in the lower- 

 most Pennsylvanian coals of Illinois. 



Chaloner's interpretation of a lepido- 

 dendrid-lepidocarp flora, based on mega- 

 spores, is still applicable to the Chester as a 

 whole. From what is known of cone studies, 

 Chaloner's interpretation implies a great 



abundance of the small spores of Lycospora 

 in the Chester Series and this is borne out 

 by the study of Hoffmeister, Staplin, and 

 Malloy (1955) on the Hardinsburg Forma- 

 tion. 



PENNSYLVANIAN 



The spores reported by Arnold (1950) 

 from the Michigan Basin, with the excep- 

 tion of Triletes rugosus, compare favorably 

 with those found in coals from the Makan- 

 da Sandstone of the Caseyville Group up to 

 and in Pope Creek Coal of the Tradewater 

 Group in Illinois. The species from Ar- 

 nold's localities 9 and 11 may occur in Illi- 

 nois Caseyville coals; most, except T. rugo- 

 sus and possibly T. ramosus, from his lo- 

 calities 1, 8, and 10, also are known from 

 the "Makanda" Coals of Illinois. T. bras- 

 serti, from Arnold's localities 4 and 6, is 

 known in Illinois only from the Tarter, 

 Willis, and Pope Creek Coals of the Trade- 

 water Group. In general terms, therefore, 

 the spores described from the Michigan 

 Basin by Arnold (1950) are similar to those 

 commonly found in coals of the upper part 

 of the Caseyville Group and the lower part 

 of the Tradewater Group. 



Bailey (1936) , in a description of micro- 

 fossils from the shales of the Cherokee For- 

 mation and lower part of the Henrietta 

 Formation of central Missouri, illustrated 

 and discussed a few megaspores. His illus- 

 trations imply that he found spores of Tri- 

 letes auritus and T. mamillarius in a sink- 

 hole or channel-fill deposit at the base of 

 the Pennsylvanian section, spores of T. 

 augustae from the Bevier (?) Coal, Cysto- 

 sporites? and weakly to strongly apiculate 

 aphanozonate megaspores from the Tebo 

 Coal. Abortive and small, apiculate aphan- 

 ozonate megaspores are illustrated from the 

 Mulky Coal. In general, the stratigraphic 

 occurrences of the spores that Bailey illus- 

 trated are concordant with the occurrence 

 of similar spores in the coals of the Illinois 

 Basin. 



A discussion of Schopf 's (1936a, 1936b, 

 1938) extensive studies on the megaspores 

 of the Herrin (No. 6) Coal of Illinois has 

 been included in previous discussion of 

 that coal. The assemblage of that coal is 



