104 PALEONTOLOGY OF THE KRUREKA DISTRICT. 
Cyathophyllum corniculum Milne-Edwards? See Geol. Sury. 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 species. Until more perfect specimens are obtained a 
provisional reference is made as above. 
Cyathophyllum rugosum Edwards and Haime. See Geol. Surv. Michigan, vol. iii, pt. 2, p. 
106. 1876. 
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™" to 25™" 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 lamelle. 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 wanting the broad margin to the calyx, the deep depression occu- 
pying the entire area. 
The lamelle are crenulated on the margin and number from 50 to 60 
in the circumference of the calyx. 
