Upper Helderberg Group. 449 



Blothrophyllum sinuosuh, n. sp. 



Corallum simple, elongate, nearly cylindrical ; all the specimens ob- 

 served are in a decorticated condition ; diameter from 15 to 20 mm.; 

 fragments of 150 mm. in length occur of uniform diameter; number 

 of lamellae from 60 to 70, alternating in size, the smaller ones being 

 about one-half the thickness of the others, the principal ones extend 

 nearly to the center of the calix, the extremities becoming slightly 

 twisted; a space of from 2 to 3 mm. in diameter at the center smooth ; 

 the tabulae are slightly concave, the outer portion bending abruptly 

 downward at right angles so that in a longitudinal section the broken 

 edges of the outer portion appear as a vertical wall,, resembling Dip- 



HYPHVLLUM. 



Formation and locality. Oorniferous limestone, Falls of the Ohio. 



Blothrophyllum promissum, n. sp. 



Corallum simple, cylindrical, elongate, diameter from 15 to 25 mm. ; 

 number of lamellae 70, alternating in size ; at the bottom of the calix 

 is a flat area, either smooth or with the lamellae but faintly indicated. 

 In the decorticated condition in which this species and B. sinuosum 

 occur it is not possible to separate them by external characters, but 

 the calix in one species has the lamellae extending nearly to the cen- 

 ter, abruptly ending and the extremities twisted, and the other having 

 a broad, smooth space at the bottom of the calix and lamellae not 

 twisted ; these characters render a distinction of the species easy. 



Formation and locality. Corniferous limestone, Falls of the 

 Ohio. 



HELIOPHYLLUM, Hall. 



Heliophyllum alterhatum, n. sp, 



Corallum simple, turbinate, usually straight, height 45 mm.; diameter 

 of calix 35 mm., depth 20 mm., sides nearly vertical, bottom flat ; 

 number of lamellae from 70 to 80, alternating in size, the larger ones 

 being very prominent, extending nearly to the center of the cup, coalesc- 

 ing and forming, small, irregular, central elevations. At the mar- 

 gin of the calix the lamellae are thick, rounded, growing thinner as 

 they approach the bottom of the calix ; denticulations of the lamellae 

 prominent, appearing as spinules, six in the space of 5 mm. This 

 species may be distinguished by the pronounced difference in the 

 size of the lamellae and the nearly vertical sides of the calix. 



Formation and locality. Corniferous limestone, Falls of the 

 Ohio. 



[Sen. Doc. No. 38.] 57 



