10 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 445 



Description. — The spores are radial, trilete, and circular to subcircular 

 in outline. The rays are distinct, straight, and extend about two-thirds the length 

 of the spore radius. The well developed area contagionis is thicker and darker 

 than the rest of the exine, which is about 3 (jl thick. The spore wall is very finely 

 scabrate to punctate. Maximum diameter of spores (2 specimens) is 100 and 90.4 jx, 



Comparison. — Except for the prominent area contagionis , this species is 

 very similar to P. aerarius Butterworth and Williams, 19 58. 



Genus CALAMOSPORA Schopf, Wilson, and Bentall, 1944 



Type species. — C. hartungiana Schopf (in Schopf, Wilson, and Bentall, 

 1944). ~~ 



Calamospora atava (Naumova) McGregor, 1964 

 Plate 3, figure 6 



Genus RETUSOTRILETES (Naumova) Streel, 1964 

 Type species. — R.. simplex Naumova, 1953. 



Retusotriletes cf. simplex Naumova, 1953 

 Plate 3, figure 7 



Discussion. — The maximum size of R. simplex of 35 \x, given by Naumova 

 (1953), was extended upward to 61 and 65 jji by de Jersey (1966) and Schultz (1968), 

 respectively. The spore illustrated in this report is also considerably larger (64 \±) 

 and thinner than the spores described by Naumova. Until more data become avail- 

 able, this larger form, which may represent a different species, is only compared 

 with R. simplex . 



Retusotriletes obscurus Peppers sp. nov. 

 Plate 3, figures 8-9 



Description. — The spores are radial, trilete, and circular to subcircular in 

 outline. The rays are distinct, often sinuous, and extend one -half to two -thirds 

 the distance to the spore margin. The raised lips are about 3 |jl wide and are dark- 

 er and thicker than the rest of the spore coat. The curvaturae are visible but not 

 conspicuous. The exine is laevigate and infra -punctate . The exine is 3.5 to 

 6 \x thick. Size range (20 specimens): 83.5 to 126.8 |jl; median, 102 jo. . 



Holotype . — Plate 3, figure 8; maceration 1510, slide 4, coordinates 141.0 

 x 42.3; size, 102.1 by 94.3 \i m 



Paratype. — Plate 3, figure 9; maceration 1510, slide 7, coordinates 127.6 

 x 52.5; size, 126.8 by 120.3 \x. 



