104 PALEONTOLOGY OF THE EUREKA DISTRICT. 



Cyathophyllum corniculum Milne-Edwards? See Geol. Stirv. Michigan, vol. iii,pt. 2, p. 102. 



A direct comparison with examples of this species from the Upper 

 Helderberg limestones at the Falls of the Ohio shows very little difference 

 between them and a similar form from the upper beds at The Gate, north- 

 west of Eureka, where it is associated with Syringopora Hisingeri, another 

 Upper Helderberg 1 species. Until more perfect specimens are obtained a 

 provisional reference is made as above. 



CyathophyUum rugosum Edwards and Hairae. See Geol. Surv. Michigail, VO'1. iii, pt. 2, p. 

 JOG. 1870. 



Well-marked silicified specimens of this species occur in association 

 with Cyathophyllum Davidsoni and Diphyphyllum Simcoense, in the Lower 

 Devonian of Lone Mountain. They are usually more or less subhemis- 

 pherical masses with occasional cells of much larger size than distinguished 

 the Upper Helderberg examples from the Falls of the Ohio; otherwise no 

 essential differences were observed. 



Cyathophyllum Davidsoni Milne-Edwards. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 107. 

 1876. 



Occurs with the preceding species, and is readily identified with the 

 forms from the Hamilton Group of Iowa. It appears to be little more than 

 a small-celled form of the associated C. rugosum. 



Cyathophyllum, n. sp. 



A compound corallum formed of corallites that increase by calicular 

 and interstitial gemmation. The corallites are usually circular, and vary 

 from 3 mm to 25 mm in diameter in the same specimen. Frequently several will 

 spring from the calyx of an old corallite, increase rapidly in size, forming 

 a subturbinate form, with a calyx broad and expanded about the margin, 

 and having a rather deep central depression, the bottom of which is sometimes 

 evenly rounded, and again with a small central protuberance formed by the 

 union of the radiating lamellae. The interstitial corallites start from the sides 

 of the older ones and arise alongside, usually remaining at the same rela- 

 tive height with the general surface of the corallum; the young or smaller 

 corallites vyanting the broad margin to the calyx, the deep depression occu- 

 pying the entire area. 



The lamellae are crenulated on the margin and number from 50 to 60 

 in the circumference of the calyx. 



