Upper Helderberg Group. 443 



distinct, 6 in the space of 10 mm.; when decorticated the corallum 

 presents an invaginated appearance ; internal striae irregular and in- 

 terrupted ; height of corallum 200 mm. or more ; calix infundibuliform, 

 diameter 50 mm., depth 40 mm.; fossette extending from near the 

 center to the margin, moderately conspicuous ; number of lamellae 

 110, of uniform size, extending to or nearly to the center ; interlam- 

 ellar cysts prominent, more conspicuous than the lamellae, which they 

 sometimes almost entirely obscure. 



The tabulae are not distinct and it is possible that they do not exist 

 in which case this species must be placed in the genus Elasmo- 



PHYLLUM. 



Formation and locality. Oorniferous limestone, Leroy, New York. 



Cyathophyllttm exfoliatum, n. sp. 



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

 concentric wrinkles and undulations of growth; external striae 

 conspicuous, 6 in the space of 10 mm.; length of an adult individual 

 from 80 to 90 mm.; diameter of the calix 35 mm., depth 25 mm., sides 

 quite regularly sloping to the center ; number of lamellae 60, broad, 

 rounded and of uniform size at the margin, becoming thinner and 

 alternating below, the principal lamellae extending to the center, where 

 they are twisted, not elevated. In a section the corallum has the 

 appearance of being formed of very thin superimposed laminae ; when 

 partially decorticated the exterior has the appearance of a Cystipliyl- 

 lum ; these characters and the flat, fragile appearance of the lamellae 

 near the margin readily distinguish it from any other species. 



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



Oyathophyllum cajs'aliculatum, n. sp. 



Corallum simple, elongate turbinate or sub-cylindrical, massive; in 

 decorticated specimens internal striae irregular, interrupted ; the largest 

 fragment observed has a height of 150 mm., diameter for nearly the en- 

 tire length 50 mm. From the nearly uniform diameter of this speci- 

 men it is evident that the length of a perfect individual would be 

 much greater than that given above ; number of lamellae about 220, 

 alternating in size, the smaller ones being scarcely more ' than rudi- 

 mentary, the principal ones continuing to the bottom of the calix, where 

 there is an elevation 40 mm . in length and 20 mm. in breadth ; where 

 the lamellae are broken away it has an elevation of about 10 mm., 

 where they are perfect it is slightly elevated, and along the middle is 

 a deep depression, which is a continuation of the lateral fossette ; the 

 bottom of the calix has a close resemblance to that of Zaphrentis com- 

 pressa, but in other respects the two forms are extremely different. 



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



