28 



ILLINOIS STATE GEOLOGICAL SURVEY 



the Caseyville and Tradewater Groups and 

 are present in other coals of these groups. 

 Smooth aphanozonate megaspores first oc- 

 cur abundantly in the Summum (No. 4) 

 Coal of the Carbondale Group and gener- 

 ally are present in the younger coals of the 

 Carbondale and McLeansboro Groups. As 

 yet, no characteristically aphanozonate 

 spores are known from coals in the Chester 

 Series. 



Triletes glabratus Zerndt, 1930 (sensu 

 Dijkstra, 1946) 



Plate 6, figures 7-10 



1930 Triletes type I Kidston, Triletes glabratus 

 Zerndt (1930c), p. 43-45; p. 1, figs. 1-3. 



1946 Triletes glabratus Zerndt, in Dijkstra, p. 26- 

 28; pi. 1, figs. 1-3, 5-8; pi. 4, fig. 35. 



Description. — Spores generally large, un- 

 ornamented, round to oval in outline when 

 mature, more subtriangular when imma- 

 ture. Spores commonly proximo-distally 

 compressed, originally saucer-shaped. Spore 

 size ranging between 400 ^ and 3000 ^, com- 

 monly between 1700 fx and 2500 M . Trilete 

 rays distinct, generally thin, equal in 

 length to one-third to one-half the spore 

 radius. Contact areas lighter in color (pi. 

 6, figs. 8, 10) by both reflected and trans- 

 mitted light, in some specimens bounded 

 by low arcuate ridges. Haptotypic features 

 generally strongly developed on immature 

 spores (pi. 6, fig. 7). Spore coat 25 to 40 p 

 or more thick, smooth, dull to bright black 

 or dark brown by reflected light, deep red 

 by transmitted light. 



Discussion. — A few poorly preserved 

 spores of this species were found in the 

 "Makanda" Coals. They range from 1265 

 to 2035 fx in diameter (six specimens meas- 

 ured dry). The spore coat on one spore is 

 41 fx thick. Well preserved spores, as illus- 

 trated on plate 6, were found in the coals 

 of the Carbondale and McLeansboro 

 Groups. Immature spores (pi. 6, fig. 7) are 

 rare. They were found only in the Sum- 

 mum (No. 4) and Grape Creek (No. 6) 

 Coals, together with many mature spores. 



Dijkstra's (1946) broad taxonomic cir- 

 cumscription of this species seems justified 

 in view of the size variation of this type of 



megaspore found by Bochenski (1936) in 

 Sigillariostrobus. According to Dijkstra 



(1955a) these spores may occur throughout 

 the Westphalian in various coal basins, but 

 are restricted to a part of the Westphalian 

 in some basins. This species is also re- 

 corded from the Stephanian of Bohemia. 

 Schopf (1938, p. 25-26) pointed out that 

 because these spores are long-ranging strati- 

 graphically, their chief value is as an eco- 

 logic indicator for certain larger lycopods. 

 The large size of these megaspores probably 

 prohibits their distribution at any great 

 distance from their point of origin. 



Occurrence. — A few apparently smooth 

 spores of this species first occur in the "Ma- 

 kanda" Coals (macerations 142, 906, 907) 

 of the Caseyville Group. This species is 

 not represented in the coals of the Trade- 

 water Group. The spores occur again, com- 

 monly, in the Summum (No. 4) Coal (mac- 

 eration 463) of the Carbondale Group. 

 They are present to abundant in the No. 

 5 Coal (macerations 630, 583, and 879). 

 They are, however, rare in the Briar Hill 



(No. 5a) Coal (maceration 633B) , but 

 abundant in the Grape Creek (No. 6) Coal 



(maceration 878). The most common meg- 

 aspore in the Herrin (No. 6) Coal (Schopf, 

 1938) is of this species. In the McLeans- 

 boro Group, these spores are abundant to 

 present in the Indiana VII (?) (maceration 

 939A), "LaSalle" (maceration 600), Friends- 

 ville (maceration 135), "Merom" (macera- 

 tion 146), "Divide" (maceration 811), and 

 "Woodbury" (maceration 703) Coals. This 

 species is also known from the Danville 



(No. 7) and Macoupin Coals. 



Triletes mamillarius Bartlett, 1929 

 (sensu Dijkstra, 1946) 



Plate 7, figures 1-6; text figure 3 



1929 Triletes mamillarius Bartlett, p. 21; pi. XIII, 

 figs. 1, 2; pi. XIV; pi. XV, figs. 1, 2. 



1946 Triletes mamillarius Bartlett, in Dijkstra, p. 

 28-31; pi. 2, figs. 9-12; pi. 3, figs. 13-15; pi. 8, 

 fig. 78. 



Description. — Megaspores from the Wil- 

 lis Coal, of medium to large size, round to 

 oval in outline, subtriangular when imma- 

 ture (pi. 7, fig. 1) (abnormal or abortive ac- 



