10 



ILLINOIS STATE GEOLOGICAL SURVEY 



Many contributions to the study of small 

 spores, megaspores, and spores in organic 

 association in cones have been made since 

 1944. Those particularly pertinent to the 

 study of larger plant microfossils of Car- 

 boniferous age outside the United States 

 are studies by Dijkstra (1946; 1952a, b, c; 

 1955a, b, c; 1957), Kalibova (1951), Pierart 

 1956, 1957), Potonie (1954a, b), Potonie 

 and Kremp (1954, 1955, 1956), and Horst 

 (1955). Recent cone studies by Chaloner 

 (1951; 1952; 1953a, b, c; 1954a; 1958a), 

 Dijkstra (1958), Remy and Remy (1956), 

 and, in the United States, by Felix (1954), 

 Hoskins and Abbott (1956), and Chaloner 

 (1956a, 1958a) to mention a few, give much 

 valuable information as to the amount of 

 natural variation in megaspores and their 

 botanical alliances. 



Particularly pertinent studies on mega- 

 spores and other plant fragments of upper 

 Mississippian and/or Pennsylvanian age 

 done in the United States are those by Cross 

 (1947), Arnold (1948, 1950), Schemel 

 (1950a), Chaloner (1954b), and Guennel 

 (1954). Cross (1947) illustrated and briefly 

 described megaspores found in coals of the 

 Kanawha Group (Pottsville Series), Alle- 

 gheny Series, and Monongahela Series from 

 the Pennsylvanian of West Virginia and 

 Kentucky. 



Arnold (1948) described several types of 

 seed membranes found in the Pennsyl- 

 vanian coals of the Michigan Basin and 

 (1950) described and illustrated some of 

 the megaspores found there. Schemel 

 (1950a), in a report emphasizing small 

 spores, described megaspores of two species 

 from a Chester or Springer age coal of 

 Utah. Chaloner (1954b) described and 

 illustrated megaspores of Kinderhook or 

 Osage age and of early Chester age from 

 Michigan, Pennsylvania, and Indiana. 

 Guennel (1954) gave a detailed description 

 of spores of Triletes triangulatus from the 

 Block Coal of Indiana. 



The study of spores contained in coal 

 macerations began at the Illinois State Geo- 

 logical Survey in 1931, under the supervi- 

 sion of G. H. Cady, with an investigation 

 of plant remains in maceration residues 



from column samples of the Herrin (No. 6) 

 Coal of the Carbondale Group. McCabe 

 (1931) illustrated some cuticle, vascular 

 tissue, and spores from the Pope Creek and 

 No. 5 Coals and (1933) reported his find- 

 ings on the plant remains of the Herrin 

 (No. 6) Coal in an unpublished doctoral 

 dissertation at the University of Illinois. 

 Henbest (1933) described some of the plant 

 fragments of the Herrin (No. 6) Coal and 

 (1935) described and illustrated a few meg- 

 aspores of that coal. 



Schopf (1936a, b) also illustrated mega- 

 spores of the Herrin (No. 6) Coal and de- 

 scribed them under binomial designations. 

 In 1938 he presented the detailed results of 

 these investigations on the large spores, in- 

 cluding prepollen, found in maceration 

 residues of the Herrin (No. 6) Coal from 

 southern Illinois. Other papers by Schopf 

 (1941a, b; 1948), mainly on fructifications 

 and seeds, presented aspects of the natural 

 affinities and variations of spores. In 1944, 

 Schopf, Wilson, and Bentall discussed the 

 generic groups of Paleozoic spores. Later 

 Schopf (1949) commented further on the 

 taxonomic identity of some spores and re- 

 viewed some of the important spore studies. 



Most previously published work on Illi- 

 nois coal megaspores emphasizes the mega- 

 spores of individual commercially impor- 

 tant coals. The present study provides a gen- 

 eral framework within which investigations 

 concentrated on one or several coals over a 

 large area can be related and therefore as- 

 sume greater significance. 



PREPARATION AND EXAMINATION 

 OF SAMPLES 



The process of coal maceration, the free- 

 ing of resistant plant parts from the rest of 

 the coal, as used at the Illinois State Geo- 

 logical Survey, is a modification (see Ko- 

 sanke, 1950, p. 8-11) of the method first de- 

 scribed by Franz Schulze in 1855. In gen- 

 eral the process consists of two phases: the 

 partial oxidation of coal with Schulze's solu- 

 tion (1 part aqueous solution of KClOo to 

 2 parts concentrated HNO ;! ), followed by 

 the solution of the salts of the humic acids 



