280 PALiEONTOLOGY. 



the Coal-Measures, but our shell differs from all of them in the proportionate 

 size of the whorls, in the form of the umbilicus, and in the form and dispo- 

 sition of the septa to such an extent as to be not readily mistaken. 



Formation and locality. — In black shale of the Coal-Measures, near 

 Eberhardt Mill, White Pine, associated with Cyrtoceras cessator and Cardio- 

 morpha Missouriensis. Collected by Arnold Hague, esq. 



FOSSILS OF-THE TRIASSIC FORMATION. 

 RADIATA. 



ECHINODERMATA. 



Genus PENTACRINITES Miller. 

 Pentackinites asteriscus ?. 



Plate VI, fig. 16. 

 f Pentacrinites asteriscus M. & H., Proc. Arad. N. Sci. Phil., 1858, p. 49; 18G0, p. 419; 

 Pal. Up. Missouri, p. 07, pi. 3, fig. 2. 



Several specimens of the separated disks of a Pentacrinites very simi- 

 lar in character to P. asteriscus M. & H., but differing somewhat in form, 

 but more particularly in their larger size, have been noticed among the col- 

 lections from Dun Glen Pass, Pah-Ute Range. When compai'ed with speci- 

 mens of that species from localities of Jurassic age, they differ slightly in 

 the more obtuse points of the star, and the filling up of the angles between 

 the points, and also in the broader form of the elliptical figures on the ar- 

 ticulating surfaces of the disks. As these features, however, are not constant 

 among any considerable number of specimens of that species, even when 

 found together on the same block, we hesitate to consider them of specific 

 importance. The large size is the most noticeable feature of these speci- 

 mens, some of which exceed one-fourth of an inch in diameter, while those 

 of that species seldom reach one-fifth of an inch, and are usually much 

 smaller. It is possible that this may prove to be a very distinct fonn when 



