26 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 480 



on those from the Herrin Coal. No plants were described from the then oldest 

 known coal-ball horizon in the Illinois Basin, the one reported by Feliciano (1924) 

 and sampled by Noe (1925a) . Feliciano identified the coal as the Indiana Coal II 

 at the Silver Island Strip Mine, Cayuga, Indiana. Schopf (1941a) later pointed out 

 that, according to Wanless (1939), the coal balls were from the Minshall Coal, 

 not the Indiana Coal II. Noe 1 s collection notes indicate the locality as Silver- 

 wood, Fountain County, Indiana. The identity of this coal is at present under in- 

 vestigation, but it is a little above the Minshall and probably equivalent to the 

 Murphy sboro Coal Member of Illinois. No further mention was made of the coal 

 ball from Sturgis, Kentucky, that Noe' (1923b) had originally mentioned as being 

 the first. 



Techniques Used in Studying Coal Balls 



In Noe's laboratory, fossils were prepared for study by making thin sec- 

 tions. Bartoo described this cumbersome technique: 



...[Noe] had a supply of coal balls which he had collected in large sacks 

 in his laboratory workshop in the basement of Hull Botanical Laboratory 

 Building, where in the northwest corner next to an outside window stood 

 the large bandsaw, next to it the rotary saw with which we "sliced" the 

 coal balls and across on the opposite side of the room a couple of polish- 

 ing laps at which we took turns working when we were in class, and I later 

 worked at alone when doing my thesis work. Hoskins and Reed had both sec- 

 tioned and worked in the same room, as far as I know, before me. It was 

 before the days of the "peel" method, so each section had to be carefully 

 glued with marine glue to the slide and polished until thin enough to see 

 through (and sometimes was lost in the process). I well remember the first 

 time Dr. Noe" showed us the new method, but it was too late to save some of 

 the material which had been lost in our grinding away at the wheel. 



Preparation of sections was vastly improved when thin sectioning was re- 

 placed by the liquid peel technique, which involved etching with hydrochloric 

 acid and re- embedding the cell walls of plants in a liquid parlodion solution 

 (Walton, 1928; Walton and Koopmans, 1928; Noe, 1930b; Graham, 1933; Darrah, 

 1936b) . When the parlodion dried, it was peeled from the specimen, and the peel 

 retained the cell walls of the fossil. Peels greatly facilitated the examination of 

 larger numbers of specimens and, despite the many hours required to dry the liquid, 

 the liquid peel technique was not replaced until Joy, Willis, and Lacey (1956) ap- 

 plied a preformed sheet of cellulose acetate to the etched coal-ball surface with 

 acetone. The peel is easily removed and can be mounted on a microscope slide or ex- 

 amined directly with reflected light. This is now the most frequently used technique 



University of Chicago Contributions 



Fredda Reed, who had provided some of the first detailed anatomical ac- 

 counts of plants from the Calhoun Coal in her doctoral thesis (1926), continued 

 her work on coal balls after receiving her degree. Coal-ball plants from the Har- 

 risburg (No. 5) Coal became known largely from her research (1936, 1938, 1939, 

 1941), which also included studies of plants from the Springfield Coal Member (V) 

 of the Petersburg Formation from "Polk's Patch near Brownsville" and Petersburg, 

 Indiana (Reed, 1939, 1952). While on the faculty at Mount Holyoke College, Reed 



