Upper Helderberg Group. 451 



of lamellae 70 ; of nearly uniform size at the margin, alternating on the 

 sides of the calix, the larger ones, extending to the center, straight or 

 slightly flexuous: denticulations spiniform, prominent, 3 in the space 

 of 5 mm. This species may be distinguished from H. verticale by 

 the imbricated costae and the extension of the lamellae to the center of 

 the cup. 



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



Heliophtllum verticale, n. sp. 



Corallum simple, elongate turbinate, straight or curved, very gradu- 

 ally expanding; exterior with numerous sharp ridges of growth; 

 height from 50 to 100 mm.; diameter of the calix from 25 to 30 

 mm., depth 15 mm., sides abruptly descending, a space at the bottom 

 from 10 to 15 mm. in diameter flat or slightly concave ; number of 

 lamellae from 75 to 80, alternating in size, the larger ones extending to 

 within a short distance of the center, abruptly coalescing with the 

 tabulae, leaving a flat or concave smooth space at the center ; denticu- 

 lations very prominent, spiniform, 6 in the space of 5 mm. 



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



Heliophyllum i^vaginatum, n. sp. 



Corallum elongate, gradually expanding ; when decorticated it has 

 the appearance of consisting of a series of invaginated calices ; height 

 of an adult individual thirteen centimetres; diameter of calix 50 mm. 

 depth 30 mm.; when the lamellae are perfect the calix is somewhat 

 bell-shaped, when brokeu away the sides of the calix are more nearly ver- 

 tical and the bottom is flat or elevated at the center; number of 

 lamellae 90, of nearly uniform size at the margin, alternating on the 

 sides, principal lamellae extending to the center, flexuous or slightly 

 twisted, very thin and prominent ; from 5 to 7 denticulations in the 

 space of 5 mm. extending to within 10 mm. of the center of the calix. 



Formation and locality. Oorniferous limestone, Falls of the Ohio 



Heliophyllum ^equale, n. sp. 



Corallum simple, elongate, straight or curved ; surface with angular 

 ridges of growth; height of corallum 14 centimetres; diameter of 

 calix 40 mm., depth 30 mm., somewhat bell shaped; number of 

 lamellae 90, of uniform size, very thin, a part of them extending to the 

 center are twisted and elevated ; denticulations uniform in width with 

 the lamellae, 8 in the space of 5 mm.; fossette obscure. This species 

 may be distinguished by the deep calix, very thin, uniform, closely 

 arranged lamellae and thin denticulations. 



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



