90 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 75 



EUREKIA DISSIMILIS (Walcott) 



PI. 16, fig. 12. 



Ptychoparia (Euloma ?) dissimilis Walcott, 1884, Monogr. U. S. Geol. Surv., 



8, p. 51, pi. 9, fig. 28. 

 Eurekia dissimilis Walcott, 1916, Smithsonian Misc. Coll., Vol. 64, p. 409. 



(Generic reference.) 



The original description of this imperfect cranidium suffices to 

 indicate the species, although the structure of the frontal limb is • 

 better shown in specimens obtained more recently. 



Observatio ns.—E . dis's'iiwilis differs from E. granulosa in the longer 

 and less quadrate glabella, the more posterior position of the occipital 

 furrow and ring and the less granulose surface. The frontal limb 

 is insufficiently preserved to allow a knowledge of its details. 



Formation and locality. — Upper Cambrian: (54) Secret Canyon 

 shale, New York Canyon, Eureka District, Nevada. 



EUREKIA GRANULOSA Walcott 



Plate 16, figs. 13-17 



Eurekia granulosa Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, 

 p. 57, pl. 12, fig. I. 



All that is known of this species is shown by the illustrations. 

 Tt apparently has a wide geographic distribution and may be one of 

 the Mississippi Valley forms that occurs in the Cordilleran area of 

 Nevada. 



Formation and locality. — Upper Cambrian, Hamburg ? formation : 

 (88) West side of Highland Range, 17 miles (27.4 km.) southwest 

 of Pioche, Lincoln County, Nevada. Apparently also present in the 

 Mississippi Valley, but further study is required to be certain that 

 these forms are conspecific. 



Genus HARDYIA Walcott 



Hardyia Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, p. 57. 



Description. — The glabella is rectangular in outline extending to 

 the front of the head. Two sets of very short glabellar furrows are 

 faintly indicated. The neck furrow and ring are rather large for 

 so small a trilobite. 



Fixed cheeks wide, particularly back of the eyes. Eyes small, 

 situated well forward. A narrow straight rim immediately in front 

 of the glabella. 



Other portions of this trilobite unknown, and the material avail- 

 able for study of the cranidium is not very satisfactory. 



Genotype. — Hardyia metion Walcott. 



Range. — Ozarkian ; Canadian Rockies. 



