58 



// LINOIS STATE GEOLOGICAL SUR) EY 



Cannelton Coal (maceration 780) from In- 

 diana. These spores, therefore, are a fairly 

 common constituent in the maceration 

 residues of coals in the Caseyville Group. 

 \ lew specimens are found in the Tarter 

 Coal (macerations 604A, 901, 914), in the 

 Willis (?) Coal (maceration 631), and in 

 the lower pan of the Willis Coal (macera- 

 tion 625B) . Specimens are rarely present 

 in one sample of the Rock Island (No. 1) 

 Coal (mac caal ion 599A) . 



Spencerisporites gracilis (Zerndt) 

 n. comb. 



1937 Triletes gracilis Zerndt (1937b), p. 586-587: 



pi. 10, figs. 1-10. 

 1914 Cirratriradites (?) gracilis (Zerndt) Schopf, 



Wilson, and Bentall, p. 44. 

 1946 Microsporites gracilis (Zerndt) Dijkstra, p. 



64-65. 



Spencerisporites cf. S. gracilis (Zerndt) 



Plate 13, figures 7-9 



Description. — Spores of Spencerisporites 

 cf. S. gracilis similar to those of S. cf. S. ra- 

 diatus in general body form, bladder de- 

 velopment, and compressional orientation. 

 Total diameter of spores, indudirg bladder 

 and marginal flange, from 278 to 468 ^ 

 (mean 378 ^ for 25 specimens) . Marginal 

 flange accounting for 10 to 28 percent 

 (mean 19.4 percent) of the total diameter. 

 Flange width from 25 to 65 ^ at corners of 

 bladder and from 15 to 65^ interradially. 

 More than three-fourths of the spores have 

 a flange width of more than 40 p. 



Trilete rays distinct, lips open in many 

 specimens, membranous, in some speci- 

 mens expressed as thin folds on bladder 

 (pi. 13, fig. 9). Contact areas apparently 

 not marked by radial striatums, in some 

 instances showing an anastomosing network 

 of folds similar to those developed on dis- 

 tal areas of central spore body. Bladder 

 ornamented with vague anastomosing folds, 

 in some specimens appearing radially 

 pleated and finely apiculate. Marginal 

 flange in some specimens almost smooth, 

 pleated, or ornamented with vague inter- 

 secting lines; flange generally crenulate or 

 scalloped at outer margin and in some in- 

 stances clearly demarcated from the outer 

 margin of the bladder (pi. 13, fig. 8) . 



Spore coal generally light yellow, central 

 portion slightly darker by transmitted light. 



Discussion. — These spores are very simi- 

 lar in appearance to those originally illus- 

 trated and described by Zerndt (1937b, p. 

 586-587, pi. 12) as Triletes gracilis, especial- 

 l\ id the development of a wide marginal 

 flange ("der ausserste Sporensaum" of 

 Zerndt, 1937b, p. 587). Zerndt refers to 

 small ear-like flaps on the corners, about 

 96 fx wide and 48^ long. This feature is 

 often cited as characteristic of these spores, 

 but it is not clearly described or illustrated. 

 Zerndt may have been referring to the 

 lobe-like aspect of the outer margin of the 

 bladder or the outer margin of the mar- 

 ginal flange (as shown in his figure 8 on 

 plate 12, at the upper righthand corner). 

 The spores described here may appear to 

 have a lobe-like outline at the outer mar- 

 gin of the marginal flange at two of three 

 corners (pi. 13, fig. 9), but this is caused 

 by slight folds along the margin. Because 

 the position of the ear-like lobes is not at 

 all clear from Zerndt's description or illus- 

 trations, I cannot compare adequately these 

 Illinois spores to those originally described 

 as T. gracilis by Zerndt, and have, there- 

 fore, referred to them as Spencerisporites 

 cf. S. gracilis. 



In comparison to those of Spencerispor- 

 ites cf. S. radiatus, these spores have a much 

 lighter colored central area, the proximal 

 and distal surfaces of which usually bear 

 anastomosing folds (pi. 1 3, fig. 8) . The con- 

 tact areas have no clearly defined radial 

 striations and some even lack the anasto- 

 mosing folds. The marginal rim is, with 

 few exceptions, much wider relative to 

 total spore size and is not as highly orna- 

 mented with anastomosing folds as are 

 spores of S. cf. 5. radiatus (pi. 13, fig. 6). 

 The marginal flange may be smooth and 

 may be scalloped at the edge. 



The change from the type of flange of 

 early Pennsylvanian age (pi. 13, fig. 1) to 

 the type of late Pennsylvanian age (pi. 13, 

 fig. 9) is rather gradual and no definite de- 

 lineation between spores of Spencerispor- 

 ites cf. .S'. radiatus and S. cf. S. gracilis can 

 be made on the basis of flange width alone. 



