KIN RAID CORALS FROM ILLINOIS 



389 



bone patterns with chevron-like dissepi- 

 ments bordering major septa near epitheca; 

 major septa extend three-fourths of radius, 

 dilated within tabularium, weak to partially 

 obsolete within dissepimentarium; cardinal 

 septum short, flanked by somewhat pin- 

 nately arranged major septa; counter sep- 

 tum long; minor septa obscure to obsolete. 



Longitudinal section. — Dissepiments of 

 unequal size, slightly elongate; tabulae com- 

 plete and incomplete, with moderately 

 down-turned peripheries and axial portions 

 slightly arched distally; tabular density 

 about 22 per cm.; pseudocolumella intermit- 

 tently present. 



Remarks. — Although smaller than the 

 original specimens from the Pitkin forma- 

 tion, these Illinois corals have no other dif- 

 ferentiating characteristics and are there- 

 fore considered conspecific with C. variabilis. 



Manuscript received April 6, 1944. 



The species has been previously listed as 

 "Cup coral n. gen. et. n. sp." (Easton, 1942, 

 p. 84) from the Pitkin formation. 



Occurrence. — Common near base of bed 

 11 of the measured section at the Illinois 

 locality. 



Material. — Figured plesiotypes: Illinois 

 State Geological Survey No. 3517; unfigured 

 plesiotypes: No. 3518. 



BIBLIOGRAPHY 



Easton, W. H., 1942, Pitkin limestone of north- 

 ern Arkansas: Arkansas Geol. Survey Bui. 8. 



, 1943, The fauna of the Pitkin formation of 



Arkansas: Jour. Paleontology, vol. 17, no. 2, 

 pp. 125-154. 



, 1944, Corals from the Chouteau and related 



formations of the Mississippi valley region: 

 Illinois Geol. Survey Rept. Inv. 97. 



Lamar, J. E., 1925, Geology and mineral re- 

 sources of the Carbondale quadrangle: Illinois 

 Geol. Survey Bull. 48. 



