18 ILLINOIS STATE GEOLOGICAL SURVEY CIRCULAR 445 



Miscellaneous Microfossils 



Genus LEIOSPHAERIDIA (Eisenack) Downie and Sarjeant, 1963 

 Type species. — L, baltica Eisenack, 1958. 



Leiosphaeridia sp. 

 Plate 5, figure 9 



Description. — The plant microfossils are circular, often split open, usually 

 partly corroded, and lack ornamentation. They are 18 to 2 3 \± thick. Shallow 

 circular pits with irregular margins, which may be due to bacterial action, are 

 common. Size range (10 specimens): 322 to 465 \i. 



Genus TASMANITES (Newton) Schopf, Wilson, and Bentall, 1944 

 Type species. — T. punctatus Newton, 1875. 



Tasmanites huronensis (Dawson) Winslow, 1962 

 Plate 5, figures 10-11 



Genus VERYHACHIUM (Deunff) Downie and Sarjeant, 1963 

 Type species. — V\. trisulcum Deunff, 195 8 



Veryhachium octoaster Staplin, 1961 

 Plate 5, figure 12 



Algae (?) 

 Plate 5, figures 13-14 



Description. — The spore-like bodies are circular to subcircular, usually 

 frequently folded, and often in small clusters of 6 or more individuals. They are 

 laevigate but usually badly corroded. Generally, they are 1 (j. or less in thickness, 

 but thickness often varies considerably on the same specimen. Size range is 22 

 to 45 |jl in diameter. 



Discussion. — These spore-like bodies, which were abundant in all three 

 macerations, are thought to have their affinities with the algae. 



Summary 



The spores are moderately well preserved, and the ratio of spores to fine 

 fragments of organic debris is low. Maceration 1510 of Sample no. 1 (table 3) 



