AGE RELATIONS OF COAL-BALLS 



11 



Coal-balls were obtained at about the 

 horizon of the Parker coal in Posey 

 County, Indiana, in 1938. This occur- 

 rence was first discovered by John Les- 

 ter, formerly of the Stratigraphy and 

 Paleontology Division of the Illinois 

 Geological Survey. The position of this 

 coal in the stratigraphic sequence has 

 been placed by J. M. Weller a short 

 distance above the horizon of the Lons- 

 dale limestone. Collections have been 

 made but are still unstudied, although 

 characteristic fossils of Psaronms and 

 Mycloxylon have been observed. 



Coal-balls from the Danville (No. 7) 

 coal (very near the base of the Mc- 

 Leansboro group) have been reported 

 by Feliciano (1924) and others. Coal- 

 balls reported from near New Castle, 

 Texas, cannot be definitely correlated 

 with the Danville (No. 7) coal, as the 

 chart published by Feliciano suggests, 

 and this record at present seems in- 

 conclusive because no plant material has 

 yet been reported. 



Numerous! coal-balls have been obtain- 

 ed from the Herrin (No. 6) coal at the 

 top of the Carbondale group, first re- 

 ported at Nashville, Illinois, by Cady 

 (1936). Recently other occurrences have 

 also been discovered in the Herrin coal. 

 The Harrisburg (No. 5) coal is the sec- 

 ond coal bed encountered below the 

 Herrin coal in the vicinity of Harris- 

 burg. The first American coal-ball to be 

 recognized as such was obtained from 

 the Harrisburg coal by Dr. G. H. Cady 

 and transmitted to Professor A. C. Noe 

 who later collected more of them. Sev- 

 eral studies of coal-ball plants from this 

 collection have been published by J. H. 

 Hoskins, H. V. Krick, and F. D. Reed. 



The lowest horizon in this basin to 

 have provided coal-balls is the Rock 

 Island (No. 1) coal in the upper part 

 of the Trade water group. At least five 

 thin but generally persistent coal beds 

 occur above it and below the base of 

 the Carbondale group .^ The Silverwood 

 (Silver Island) coal-ball occurrence re- 

 ported by Feliciano (Fountain County, 



^The Palzo sandstone member is now considered 

 to represent the basal bed of the Carbondale 

 group (Cady 1941). Wanless (1939) used the 

 Sebree=Isabel? sandstone as a boundary, but the 

 precise equivalence of those beds is in question 

 and the Isabel, at least, may lie somewhat higher 

 than the Palzo. 



Indiana) is in the Minshall coal which 

 is equivalent to the Rock Island coal 

 according to Wanless (1939). Coal-balls 

 have been recorded from central Iowa 

 west of Des Moines by Darrah (1939). 

 The coal is reached by shaft mines, and 

 its position is less definitely established 

 than that of the other horizons men- 

 tioned, but according to Dr. L. M. Cline 

 the coal is probably the same as Lugn's 

 (1927) Lucas County "Lower Coal", 

 which may correspond in age to the 

 Rock Island bed of Illinois. Darrah men- 

 tions that Mazocarpon occurs in these 

 coal-balls but the results of his study are 

 not yet available. Coal-balls considered 

 to be from the same horizon have been 

 obtained near Indianola, Iowa, by Hos- 

 kins and Cross (1941). Other Iowa coal- 

 ball material is being studied by L. R. 

 Wilson and his students at Coe College. 

 Feliciano also listed coal-balls col- 

 lected by Noe from Bloomfield, Davis 

 County, Iowa. The only coal-balls known 

 in this vicinity are from the Lower Sea- 

 home coal, according to recent studies 

 by Cline. This coal is above the Rock 

 Island horizon, in the upper part of the 

 Tradewater group. 



EUROPEAN COAL-BALL 

 HORIZONS 



Histologic preservations of plant de- 

 bris of lower Permian age has been re- 

 ported from western Europe in many 

 studies. Similar material of Stephanian 

 age in central France has also been the 

 subject of much investigation. Most of 

 these petrifactions are silicified. Al- 

 though the plants are comparable in 

 preservation to those from coal-balls, 

 they apparently have no relationship to 

 beds of coal, and consequently the petri- 

 factions must have been formed differ- 

 ently. They are mentioned because they 

 seem to provide the most abundant com- 

 parable paleobotanical material that is 

 younger than that in Illinois coal-balls, 

 and some of the plants found here may 

 have an ancestral relationship to some 

 found in Stephanian and lower Permian 

 deposits. 



In 1845 Corda (1867) described in 

 the "Protogaea" a few plants from the 

 coal mines near Radnitz in central Bo- 

 hemia which were histologically pre- 



