DEVELOPMENT OF PALEOBOTANY IN THE ILLINOIS BASIN 47 



Thiessen (1920, 1930), in describing his system of coal classification, 

 illustrated several thin sections of Illinois coal and several spores that had been 

 macerated from coals, among which were the Shelbyville and Herrin (No. 6) Coals 

 of Illinois. Several coals were distinguishable by the dominance of certain spore 

 taxa. 



Vertical changes in paleobotanical composition of coals revealed in thin 

 sections were considered by Ball (1932) as a possibletool in correlation of Illinois 

 coals. He remarked on the difficulty of identifying spores from various planes in 

 thin sections and thought that a classification of sporeswas needed before spores 

 could be used to any extent in correlation. 



Fieldner et al. (1932) and L. C. McCabe (1932, 1933, 1934) described and 

 illustrated some of the paleobotanical constituents of the No. 6 Coal in Illinois. 

 McCabe noted that vitrain might show the anatomy of plants, the presence of 

 branches, growth stages, and different stages of preservation. W. S. McCabe 

 (1936) etched polished surfaces of the No. 6 Coal with a mixture of sulfuric and 

 chromic acid to reveal more clearly the resins, spores, cuticles, and cell struc- 

 tures in vitrain. As mentioned in the section on palynological studies, O.J. Hen- 

 best (1933a) compared botanical constituents in macerated coal residues with the 

 constituents observed in thin sections. In a discussion of the botanical compo- 

 nents in Illinois coal, G. H. Cady (1933) illustrated thin sections showing spores, 

 resin, cuticular tissue, and xylem cell structures and compared them with macer- 

 ated material. 



In addition to his palynological investigations, Kosanke was interested in 

 broader aspects of coal composition. In 1951 he used thin sections and polished 

 sections to investigate a boghead coal from the upper part of the Tarter Coal Mem- 

 ber (Abbott Formation) of northern Illinois, which is equivalent to the Willis Coal 

 Member of southern Illinois. He compared the algal colonies in the Tarter Coal 

 with those found in boghead coals of Pennsylvania and Kentucky. Kosanke (1952) 

 presented the chemical analyses of various botanical constituents, including mega- 

 spores, cuticles, and resin rodlets of several coals from Illinois and elsewhere. 

 Resin rodlets from several Illinois coals were thought by Kosanke and Harrison 

 (1957) to be produced by the pteridosperm Medullosa . 



Anticipated Directions in Pennsylvanian Paleobotany 



The Illinois Basin is now roughly outlined by institutions with active teach- 

 ing anc^/or research programs in paleobotany, for the most part the larger universities 

 and the geological surveys (fig. 5). The number of paleobotanists at universities 

 and colleges represents a major expansion in paleobotany in the last two decades in 

 the United States. More geology, biology, and general liberal arts students are 

 being exposed to paleobotany as an interesting and active field of study. Paleo- 

 botanists, although still a small group compared to the numerous workers in other 

 areas of paleontology, are increasing in number. They are exploring new areas of 

 study and renewing interest in older areas. This intensified research is seen in 

 the rapid increase of published pages during the last 25 years. The pioneers of 

 paleobotany in the Illinois Basin have passed along important discoveries, abroad 

 understanding of Pennsylvanian plants, and basic frameworks in all branches for 

 more precise and extensive paleobotanical contributions. As more information be- 

 comes available, there is a growing need for synthesis and efficient retrieval of 

 paleobotanical data. Synthesis, particularly, is needed in paly nology. 



