MARYLAND GEOLOGICAL SURVEY 199 



Family ZAPHRENTIDAE 



Genus STREPTELAS . A Hall 



STREPTELASMA PROFUNDUM (Conrad) 



Plate XLII, Figs. 1, 2 



Cyathophyllum profundum Conrad, 1843, Proc. Acad. Nat. Sci., Philadelphia, 



p. 335. 

 Streptelasma profunda Hall, 1847, Pal. New York, vol. i, p. 49, pi. xii, 



figs. 4a-d. 

 Streptelasma profundum Winchell and Schuchert, 1895, Geol. Minnesota, 



Pal., vol. iii, pt. i, p. 88, pi. G, figs. 17-19. 



Description. " Obliquely turbinate, often slightly curved near the 

 base/ expanding above more or less abruptly; cell profoundly deep, ex- 

 tending nearly to the base of the coral ; margin of the cup reflexed ; sur- 

 face scarcely marked by transverse rugae; lamellae from 36 to 60, strong, 

 nearly equal to the margin, but distinctly alternating in length within; 

 no transverse dissepiments or celluliferous structure." Hall, 1847. 



This well-marked form can readily be separated from other species of 

 the genus by its deep, visceral cavity, by its sharply denned lateral fos- 

 sulae and great development of the primary septum, and by its septa 

 which are never twisted in approaching the center. 



Occurrence. CHAUBEKSBURG LIMESTONE (Tetradium cellulosum bed). 

 Fort Loudon, Franklin County, Pennsylvania. A characteristic and 

 abundant Black Eiver fossil of the United States and Canada. 



Collections. Maryland Geological Survey, IT. S. National Museum. 



Suborder TABULATA 

 Family CHAETETIDAE 



Genus TETRADIUM Dana 

 TETRADIUM ? SIMPLEX n. sp. 



Plate XXXIII, Figs. 13-15 



Description. The discovery of a coral in the Beekmantown limestone 

 is of especial interest since hitherto no typical representative of the corals 

 has been recorded from strata of this age. The species here noted occurs 



