8 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 445 



normal high -temperature ashing, which converts most of the minerals to oxides. 

 Some weight is regained through oxidation of iron to Fe^Oo. The 8 to 9 volume 

 percent of pyrite determined from the petrographic analysis corresponds to approxi- 

 mately 20 weight percent pyrite, which is somewhat higher than the chemical anal- 

 ysis indicates. However, rather impure pyrite -rich layers of coal were included 

 in the petrographic analysis, whereas the pieces that were submitted for chemi- 

 cal analysis had less pyrite. 



The unusually low 5.2 percent oxygen on the moisture- and ash-free basis, 

 which would normally be found in a medium volatile bituminous coal, indicates 

 that the results of the ultimate analysis are not necessarily representative for the 

 pure organic matter of this coal. 



V. E c Dow (1960, p. 255) described similar properties for a thin, slightly 

 younger coal in the Cedar Valley Limestone from three outcrops in Johnson County, 

 Iowa: thinly laminated, abundant carbonaceous material (40 to 50 percent in one 

 sample), pyrite that had been altered to limonite, and a large amount of ash (25 

 percent, as calculated on the same basis as the Illinois coal). Dow observed 

 85 to 90 percent spore exines in one thin section parallel to the bedding. The pro- 

 portion of exinite observed in a polished section of a sample of the weathered Iowa 

 coal that we prepared is more than that of the Illinois coal but is well below Dow' s 

 value. Dow also mentioned "some yellow-orange bodies of what appears to be 

 resin" in one of his thin sections, and "fish remains (plates, teeth, etc.)." 



PALYNOLOGY 



Although published investigations of Devonian palynology have increased 

 considerably in the last few years, this report is only the second concerning De- 

 vonian land plant spores in Illinois. Guennel in 1963 described Devonian spores 

 from a Silurian reef cored by a diamond drill in southern Illinois. The spores, 

 many of which were described as new, were from cavity fillings of strata younger 

 than the reef. Other publications on Devonian-dispersed land plant spores in the 

 United States are almost as scarce as those in Illinois. A monographic work on the 

 plant spores and other microfossils from Upper Devonian and Lower Mississippian 

 rocks of Ohio was prepared by Winslow in 1962. Kosanke (1964, p. 78-79), in 

 a discussion of applied Paleozoic palynology, briefly mentioned the presence of 

 spores in a coal from the Cedar Valley Limestone of Johnson County, Iowa. San- 

 ders (1967) described in detail the spores from this coal. This is the only other 

 known report of spores from a Devonian coal in the United States. 



The Solon Limestone Member of the Cedar Valley Limestone has provided 

 an extensive spore assemblage (Norton, 1967) and a new spore genus (Urban, 1968) 

 McGregor (1960, 1961, 1964, and 1967) and McGregor and Owens (1966) have con- 

 tributed a large amount of significant data on the Devonian spores of Canada. Nu- 

 merous major contributions to the knowledge of Devonian palynology come from 

 other parts of the world, but no attempt is made to review them here. 



Maceration Technique 



Samples no. 1 and 2 (macerations 1510 and 1548) were treated for about 4 

 hours with 10 percent solution of hydrochloric acid to remove the carbonate min- 

 erals, and after decanting several times, hydrofluoric acid was added to remove 

 most of the silicate minerals. These steps were omitted for Sample no. 3 (macer- 

 ation 1589). 



