16 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 445 



Spinozonotriletes cf. tuberculatus Neves and Owens, 1966 

 Plate 5, figure 1 



Discussion. — The Illinois spores have a larger size range (110.5 to 183.6 \± 

 on 20 specimens) than that reported by Neves and Owens (90 to 136 \±) for this 

 species. However, because our specimens generally conform in other respects to 

 the British spores, they are assigned to this taxon. 



Spinozonotriletes cf. naumovii (Kedo) Richardson, 1965 

 Plate 5, figure 2 



Discussion. — Apparently the principal differences between S_, naumovii and 

 S. tuberculatus Neves and Owens, 1966, are that the former has a thicker intexine 

 and smaller spines. 



Spinozonotriletes (?) sp. 

 Plate 5, figure 3 



Description. — The spore is radial, trilete, and roundly triangular in outline. 

 A commissure is not apparent, but the rays that are delineated by prominent lips 

 or folds extend almost to the spore margin. The exine is in two parts — a thin cen- 

 tral region that extends to about one -third the spore radius and a thick zona or cingu 

 lum that gradually tapers in thickness toward the equator. No intexine is visible. 

 Under oil immersion objective the exine is infra -punctate and presents a spongy 

 appearance. On the entire distal side are moderately spaced large spines, 16 to 

 23 \i long and 5 to 8.5 [± wide at their bases. They have tapered to sharply pointed 

 ends. Approximately 32 of these spines extend beyond the spore periphery. The 

 diameter is 195 by 177 \±. 



Genus ARCHAEOZONOTRILETES (Naumova) Allen, 1965 

 Type species. — A. variabilis Naumova, 1953. 



Archaeozonotriletes cf. purus Naumova, 1953 

 Plate 5, figure 4 



Description. — The spore is radial, trilete, and circular in outline. The 

 laesurae are distinct, simple, and extend almost to the margin of the central area 

 or intexine, which is obliquely displaced. The exine is laevigate and infra-punc- 

 tate. The distal side is only slightly thicker than the proximal size. The over-all 

 diameter is 54 . 3 by 5 1 . |jl; the intexine is 44.5 by 41.3 \±. 



Comparison. — Naumova' s (1953) size range of 30 to 35 \± is quite small 

 compared with the Illinois spore. However, it is not unreasonable to assume that 

 the size range could be more than 5 \±. 



Archaeozonotriletes sp. 

 Plate 5, figure 5 



