Upper Helderberg Group. 455 



Heliophyllum aequum, n. sp.' 



Oorallum simple, more or less curved, when decorticated presenting 

 a decidedly invaginated appearance ; height 50 mm., diameter of the 

 calix 30 mm., depth 20 mm., the margin sub-quadrangular in outline, 

 sides nearly vertical, an area at the bottom 15 mm. in diameter flat, 

 smooth ; number of lamellae 90, alternating in size, the larger ones being 

 faintly indicated for a short distance on the tabulae at the bottom of 

 the calix ; fossette narrow, deep. This species may be distinguished 

 by the broad, smooth area at the bottom of the calix. 



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



Heliophyllum scyphulus, n. sp. 



Oorallum simple, turbinate, regularly curved ; surface with frequent 

 narrow annulations of growth and fine striations, sometimes with com- 

 paratively broad undulations. The greater portion of the individuals 

 observed are from 20 to 25 mm. in height ; diameter of the calix about 

 equal to the height, depth 15 mm.; a space at the bottom of the calix, 

 when the lamellae are perfect, flat or slightly convex ; fossette situated 

 anteriorly, not extending to the margin ; number of lamellae 60, of 

 uniform size at the margin, alternating below, the larger ones extend- 

 ing to the center, slightly twisted, occasionally one or more extending 

 from margin to margin ; center of tabulae flat, the outer portion bending 

 abruptly downward ; from 3 to 5 denticulations in the space of 5 mm. 

 at a distance from the margin very prominent and spiniform. 

 This species differs from H. Haiti in the form of the calix, thinner 

 lamellae and more distant denticulations. 



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



Heliophyllum tenuimurale, n. sp. 



Oorallum simple, turbinate, curved, usually decorticated ; internal 

 costae prominent; height of corallum 30 mm.; diameter of calix 25 mm., 

 depth 15 mm., sides abruptly sloping, leaving a convex space at the 

 bottom 10 mm. in diameter ; fossette extending from near the center 

 to the anterior margin of the calix; in continuation of the fossette a 

 depression extends across the elevated space at the bottom of the caiix 

 connecting with a rudimentary fossette on the posterior side; number 

 of lamellae 90, alternating in size, the smaller ones rudimentary, the 

 larger ones extending to the center of the calix where they are elevated 

 and twisted; 7 or 8 denticulations in the space of 5 mm. 



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



Heliophyllum Nettelrothi, n. sp. 

 Oorallum simple, elongate turbinate/ regularly or irregularly curved. 

 The numerous individuals observed are decorticated ; the internal 



