Upper Helderberg Group. 441 



center, extending to those crossing the bottom, their extremities 

 coalescing* and curving. This species is very characteristic and* is 

 easily distinguished from any other. 



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



Zaphrentis elegans, n. sp. 



Corallum simple, turbinate, usually slightly compressed, acute at 

 the base, regularly expanding to the calix ; exterior with concentric 

 wrinkles and undulations, external striae distinct, 14 in the space of 10 

 mm.; when decorticated the internal striae are usually broad, equal to 

 one-half the number of the lamellae ; corallum usually about 70 mm. in 

 height, diameter of the calix 30 mm., depth 20 mm., sides abrupt, an 

 oval space at the bottom smooth or with the lamellae faintly indicated ; 

 fossette usually dextral, consisting of a deep, elongate depression at 

 the bottom of the cup, but faintly indicated on the sides ; number of 

 lamellae from 80 to 90, alternating in size, thickened and sub-angular 

 at the margin, becoming very thin and fragile below. This species 

 may be distinguished from Z. profunda by its compressed form, shal- 

 lower calix and finer lamellae ; from Z. nitida by its compressed form, 

 narrower flattened space at the bottom of the calix and somewhat 

 finer lamellae. 



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



Zaphrentis convoluta, n. sp. 



Corallum simple, turbinate, straight or regularly curved, acute at 

 the base, regularly expanding to the calix, slightly compressed, oblique; 

 decorticated specimens presenting a somewhat smooth appearance ; 

 internal striae not prominent; height of corallum 70 mm.; diameter of 

 calix 40 mm., depth 25 mm., a space at the center 12 mm. in diameter 

 flat and smooth ; number of lamellae 100, alternating in size, the 

 smaller ones about 15 mm. long; usually from 2 to 4 adjacent prin- 

 cipal lamellae coalesce and fasciculate, becoming twisted and extending 

 to within 6 mm. of the center; fossette obscure or obsolete. This 

 species may be recognized by the conspicuous coalescing and fascicu- 

 lating of the lamellae and their decided twisted appearance after coal- 

 escing. 



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



Zaphrentis contorta, n. sp. 



Corallum simple, turbinate, slightly and regularly curved ; exterior 

 quite smooth when decorticated; internal striae fine and distinct, 14 in 

 the space of 10 mm.; height of corallum 30 mm.; diameter of the calix 

 25 mm.; fossette sinistral, at the bottom deep, pyriform, narrower and 

 less conspicuous on the sides; number of lamellae from 90 to 100, alter- 

 [Sen. Doc. No. 38.] 56 



