Upper Helderberg Group. 447 



principal lamellae coalesce and fasciculate, each fascicle being composed 

 of from 2 to 7 lamellae ; after coalescing they continue nearly to the 

 center and become twisted. When the lamellae are perfect they have, 

 at their margins, slender spinules about .75 mm. in length, 8 in the 

 space of 5 mm., forming a very prominent feature, but most conspicu- 

 ous on the intermediate smaller lamellae, the margins of the principal 

 ones usually being broken. On the sides of the lamellae are rounded 

 striations continuing a short distance from the margin, but not of 

 sufficient prominence or extent to place the species in the genus Heli- 

 ophyllum. 

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



Cyathophyllum perplicatum, n. sp. 



Corallum simple, turbinate, curved, obtuse at the base, quite rapidly 

 expanding for a short distance, then continuing of nearly uniform 

 diameter; exterior with shallow grooves, concentric wrinkles and very 

 distinct, fine, concentric striae; longitudinal striae distinct, 8 in the 

 space of 5 mm.; when decorticated it presents a somewhat cystose ap- 

 pearance ; height of corallum 60 mm.; diameter of the calix 30 mm., 

 depth 10 mm., a space at the bottom 10 mm. in diameter, slightly 

 convex and corrugated ; fossette obscure or obsolete ; number of lam- 

 ellae 75, alternating in size, near the margin of the cup thickened, and 

 angular, thin below; the principal lamellae continue to the center 

 on the convex space at the bottom becoming interrupted and having the 

 appearance of corrugations. 



Formation and locality. Oorniferous limestone, Crab Orchard, 

 Kentucky. 



Cyathophyllum robustum, n. sp. 

 Corallum simple, elongate turbinate or cylindrical, when decorti- 

 cated appearing as if formed of invaginated calices, each of which con- 

 sists of thin, superimposed laminae ; external costae very distinct, 4 or 

 5 in the space of 10 mm.; concentric striae coarse, distinct; when de- 

 corticated the internal costae have numerous transverse elevations at' 

 irregular distances apart caused by the interlamellar cysts. The 

 largest fragment observed has a length of 220 mm. and a diameter of 

 110 mm. For a space of from 20 to 30 mm. from the margin the sides 

 of the calix are sloping at an angle of about 45° to the axis of the cor- 

 allum, becoming vertical, then becoming flat for a width of 10 mm., 

 thence abruptly descending, frequently to a depth of 30 mm.; this deep 

 depression has at first a diameter of about 20 mm., gradually narrowing 

 below; number of lamellae from 100 to 130, alternating in size, the prin- 

 cipal ones extending nearly to the flat tabula at the bottom of the 



