8 GEOLOGICAL SURVEY OF THE TERRITORIES. 
Genus BEAUMONTIA Edwards & Haime. 
BEAUMONTIA ? SOLITARIA (Sp. NOv.). 
Plate 12, figs. 13 a, b, and c¢. 
Beaumontia ? solitaria White, 1879, Bull. U. 8. Geol. Sur. Terr., vol. v, p. 221. 
Corallum massive, compact; corallites prismatic, readily cleaving 
from each other in the specimens discovered, unequal in size and also 
in the shape of the transverse section, some of them being more than 
twice as large as others, and the longer diameter of some being more 
than twice as great as the short diameter of thesame; average diameter 
of the corallites not exceeding one millimeter; their walls thin, appar- 
ently marked only by the ordinary lines of growth; tabule plain, numer- 
ous, variously flexed, but never to a great degree. No trace of radiate 
septa or of longitudinal striation of the corallites has been detected. 
This coral much resembles Favosites in the character of the corallum 
and the aspect of the corallites, but no traces of mural pores have been 
detected, not even in the section prepared by Professor Nicholson, when 
viewed under the microscope. In consequence of this, and of the irregu- 
lar or flexed character of the tabule, I refer it to Beaumontia. Appar- 
ently the only known fact that suggests a doubt of the correctness of 
such a reference is that Beawmontia has hitherto been known only in 
Paleozoic rocks. This is also a rare form, and doubtless so for the 
reasons explained in connection with the description of the foregoing 
species. 
Position and locality—Associated with the preceding and various 
molluscan forms in Cretaceous strata of the Fox Hills Group, Northern 
Colorado. 
ECHINODERMATA. 
Genus OPHIODERMA. 
OPHIODERMA? BRIDGERENSIS Meek. 
Plate 12, fig. 12 a. 
Ophioderma? bridgerensis Meek, 1873, An. Rep. U. S. Geol. Sur. Terr. for 1872, p- 475. 
The type specimen from which Mr. Meek drew his description, and 
from which the figure on plate 12 is drawn, is the only example of the 
species that, has ever been discovered. Therefore nothing more is known 
of it than was published (loc. cit.) by Mr. Meek. It was obtained by one 
of the parties of the Survey from the “last foot of Bridger Peak, 4 miles 
north of Fort Ellis, Mont.,” where it is reported to be associated with 
certain imperfect molluscan remains, among which Mr. Meek recognized 
the following genera, namely: Gryphea, Avicula, Pinna, Inoceramus, 
Crassatella, Pholadomya, Turritella, and Gyrodes. 
The following is Mr. Meek’s brief deseription: “A small Ophiuran, with 
disk depressed, nearly circular, and only 0.17 inch in breadth, showing on 
the dorsal side ten ovate-subtrigonal radial plates that are joined together 
over the inner ends of the arms, so as to form five pairs; arms small, only 
about 0.75 inch in length, and at their inner ends 0.06 inch in breadth; 
middle row of arm-pieces on the dorsal side slightly wider than long, and 
hexagonal in form; marginal pieces about as large as the middle ones, 
