Niagara Group. 417 



HELIOPHYLLUM, Hall. 



Heliophyllum gemmiferum, n. sp. 



Gorallum simple, turbinate, usually nearly straight; increasing by 

 calicular gemmation, the buds proceeding from the flat, marginal por- 

 tion of the calix, and usually turning outward at a short distance from 

 the base ; frequently 9 or 10 buds from a single corallum ; exterior with 

 numerous concentric wrinkles and striations, and frequent processes 

 which served for attachment and support ; the proportional height 

 and diameter of this species is variable, some individuals having a 

 height of 40 mm. and a diameter at the calix of 10 mm., and others 

 having a height of 30 mm. and a diameter of 30 mm. ; in a calix 20 

 mm. in diameter the sides, for a distance of 6 mm. from the margin, 

 are flat or gently sloping, then abruptly sloping toward the center 

 where there is an elevation of 5 mm. in diameter, and of nearly the 

 same height ; number of lamellae 60, of nearly uniform size at the 

 margin, thickened and gently rounded, becoming thinner and alter- 

 nating below ; on the sides the smaller ones coalesce with the others 

 which continue to the center, where they are twisted and elevated. 



Formation and locality, Niagara group, Louisville, Keutucky. 



Heliophyllum pkavum, n. sp. 



Corallum simple, elongate, turbinate, curved or tortuous, acute at 

 the base, with frequent constrictions above, not regularly expanding 

 to the calix ; exterior with numerous, narrow, angular annulations; 

 height of corallum 25 mm., diameter of the calix 10 mm., depth 5 

 mm., some individuals having a greater proportional diameter; calix 

 campanulate, a flat space 5 mm. in diameter at the bottom ; fossette 

 dextral, moderately conspicuous at the bottom, becoming obsolete be- 

 fore reaching the margin ; number of lamellae 50, of uniform thick- 

 ness, alternating in length, rounded at the margin, becoming very 

 thin as they approach the center; the shorter lamellse continue to the 

 flattened space at the bottom of the calix, the others to within a short 

 distance of the center, leaving a well-defined concave space of 2 mm. 

 in length and 1 m. in width, in continuation of the fossette ; dentic- 

 ulations thin, prominent, 11 in the space of 5 mm. 



Formation and locality. Niagara group, Louisville, Kentucky. 



Heliophyllum dentili^eatum, n. sp. 



Corallum simple, elongate, turbinate or sub-cylindrical, with fre- 

 quent constrictions, not regularly expanding to the calix ; diameter 

 of the calix 10 mm., depth 5 mm.; sides vertical, bottom slightly con- 

 vex ; tabulae broad, extending nearly the entire diameter of the coral- 

 [Sen. Doc. No. 38.] 53 



