GENUS SPENCERISPORITES 



57 



ally from a central area on the contact sur- 

 face. Radial striations sometimes appearing 

 as coarse gouges (pi. 13, fig. 3) , as opposed 

 to more delicate sinuous striations as shown 

 by figure 5b on plate 13. 



Distal side of spore body and, in some 

 specimens, distal surface of bladder appear 

 smooth. Proximal surface of bladder and 

 marginal flange ornamented with vague in- 

 tersecting or anastomosing fine folds. 



Spores golden to brownish yellow cen- 

 trally, generally very light yellow at flange 

 by transmitted light. 



Discussion. — In most details of spore 

 morphology these spores, although some- 

 what larger, agree with those of Spenceri- 

 sporites karczewskii and of Spencer ites in- 

 signis as described by Chaloner (1951) . On 

 one specimen the distal spore body coat is 

 twice as thick (4 y) as the thickness given 

 by Chaloner. Measurements of the diame- 

 ter of the spore body, or body cavity, are 

 not given here because it is not measurable 

 with accuracy on compressed specimens. 

 The compressed specimens studied agree 

 with Chaloner's interpretation that the 

 marginal flange is a single membrane (al- 

 though Potonie and Kremp [1956] regarded 

 it as two membranes) contiguous with the 

 upper surface of the bladder. 



The radial striations on each contact 

 face do not all radiate from a common 

 point in the center. More or less parallel 

 lines extend nearly through the center of 

 each contact face from the corners of the 

 spore body. The lines, both towards the 

 apex and towards the margin of the spore 

 body, become more and more flexed near 

 their midpoints (pi. 13, fig. 5b) . The gen- 

 eral aspect is of slightly superimposed 

 finger-prints on each contact area, and al- 

 though on some specimens (pi. 13, fig. 3) 

 the lines appear straight and as gouges, the 

 pattern is more or less the same. These 

 lines also appear to extend slightly onto 

 the bladder but end at the base of the lips. 

 Spores of two slightly different aspects 

 are included in this species because inter- 

 grading or transitional forms are numerous, 

 and any distinction, at present, would have 

 to be based on arbitrary numerical values, 

 for example, for width of the marginal 



flange. Those spores of the lowest coal in a 

 diamond drill core in the Caseyville Group 

 (pi. 13, fig. 3) in Wabash County, Illinois, 

 generally have a narrow marginal flange 

 that accounts for 10 percent or less of the 

 total diameter, and some specimens possess 

 a flange so narrow that it is barely notice- 

 able. The intersecting lines on the bladder 

 generally are vague. The trilete rays in 

 some specimens are expressed as folds on 

 the bladder. They are similar to those illus- 

 trated by Horst (1955, pi. 18, fig. 15; pi. 19, 

 fig. 16) from the Hruschau zone of the Na- 

 murian A in the Mahrische-Ostrau region. 

 Smaller but seeminglv related spores re- 

 ported by Dijkstra (1957) as Endosporites 

 chaloneri occur in the coal beds of the 

 Limestone Coal Group of Scotland. In con- 

 tradistinction, those found in the Reynolds- 

 burg Coal appear to have a generally wider 

 marginal flange accounting for up to 18 

 percent of the total diameter. A more con- 

 spicuous ornamentation appears on the 

 bladder, in some cases even apiculations, 

 and the rays are more commonly expressed 

 as folds on the bladder. 



The spores of this species are distinguish- 

 able from those of Spencerisporites cf. S. 

 gracilis by the presence of radial striations 

 on the contact areas and by a generally 

 narrower marginal flange. 



Previously reported occurrences of spores 

 referable to Spencerisporites radiatus are 

 given in Diikstra (1946) and Potonie and 

 Kremp (1956). In general this species is 

 represented in the Namurian A, B?, and 

 C? and in the Westphalian A, B, C, and 

 D?. 



Occurrence.— These spores are most 

 abundant, even occurring in masses, in the 

 lowest coal in a diamond drill core (macer- 

 ation 798) of two Wabash County cores, 

 but are rare in two of the upper coals (mac- 

 erations 795, 797) of these two cores. They 

 are rare in one sample of the Battery Rock 

 Coal (maceration 587) , but are present in 

 another sample (maceration 629) . They 

 also are present in the "Makanda" Coals 

 (macerations 905, 906) and very abundant 

 in the Reynoldsburg Coal (maceration 

 618) . They are rare in the shale above the 

 Pinnick Coal (maceration 163) and in the 



