CORALS OF THE UPPER HELDERBERG GROUP. 



STEEPTELASMA, Hall. 



Steeptelasma lamellatum, n. sp. J 3 /* 3 ~'j l 

 Corallum small, simple, turbinate, straight or slightly curved ; 

 height 40 mm.; diameter of the calix 15 mm., depth 35 mm.; 

 number of lamellae 60, alternating in size, near the center sharp, 

 thickening as they approach the margin and becoming broadly angu- 

 lar ; for a space of 1Q mm. from the margin they are denticulated, 

 the denticulations extending from one lamella to another, frequently 

 continuous and having the appearance of concentric striations ; the 

 larger lamellae continue to the center, not twisted or elevated. 

 Formation and locality. Oorniferous limestone, Canada West 



Steeptelasma tenue, n. sp. /? U &f <*- 

 Corallum small, turbinate or subcylindrical, regularly curved or 

 tortuous; surface with numerous annulations; longitudinal striae very 

 distinct; height about 35 mm. ; diameter of calix from 10 to 15 mm.; 

 depth from 15 to 20 mm. ; number of lamellae 50, alternating in 

 size, the larger ones extending nearly or quite to the center. 



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



Steeptelasma dissimile, n. sp. ?*}*d £«*V>-<C 

 Corallum simple, turbinate, regularly curved ; exterior, near the 

 base, undulating, above with numerous sharp annulations of growth ; 

 height of corallum 30 mm. ; depth of calix 20 mm., sides abruptly 

 descending ; number of lamellae 70, alternating in size, the smaller 

 ones about one-half the size of the others and becoming obsolete on 

 the sides; near the margin the lamellae are broad and rounded, grow- 

 ing thinner as they approach the center, where there is sometimes a 

 smooth space about 5 mm. in diameter, formed by the coalescing of 

 the lamellae, very oblique and nearly parallel with the anterior por- 

 tion of the lamellae. 



