FOSSILS OF THE CAMBRIAN. 03 



Surface of the glabella minutely granulose ; the frontal limb has a 

 peculiar ornamentation formed by irregular inosculating lines that in their 

 general direction radiate towards the anterior rim. 



With the portions of this species we have before us, it appears to be 

 related to Arethusina more closely than any other described genus. The 

 posterior glabellar furrows are less oblique than in the Bohemian species, 

 but otherwise there is a strong generic resemblance between them. 



Formation and localities. Upper beds of the Cambrian. On the ridge 

 north of the Dunderberg mine, at about the same horizon on the north 

 side of the canon north of Adams Hill, and also in the Pogonip Group, 

 on the second ridge southeast of the Jackson mine, Eureka District, Nevada, 



Genus OGYGIA Brongniart. 



Ogygia ? spinosa, n. sp. 



Plate ix, fig. 22. 



Glabella elongate, not quite twice as long as wide ; sides parallel 

 nearly to the front, which is slightly expanded and broadly rounded ante- 

 riorly; moderately convex and subangular along the median line; marked 

 by three pairs of oblique furrows that extend one-third the distance across; 

 occipital ring strong, not very convex, and with a rather strong central 

 spine projecting backward and upward; occipital furrow shallow, well 

 defined; fixed cheeks narrow; palpebral lobes large, rising slightly from 

 the dorsal furrows to the depressed furrow just within and parallel to their 

 margins; frontal limb convex, of medium width and length, and bordered 

 by a flattened rim. The presence of the strong occipital spine is one of 

 the most distinct characters of this species. 



Formation and locality. Cambrian. Prospect Mountain Group; at the 

 base of the Secret Canon shale in Secret Canon, Eureka District, Nevada. 



Ogygia ? problematica, n. sp. 

 Plate x, tigs. 2a-6, and 4. 



Glabella elongate, clavate, expanding regularly from the base to a 

 width one-third greater in front; moderately convex behind, becoming 



