NO. 3 CAMBRIAN AND OZARKIAN TRILOBITES 85 



DUNDERBERGIA NITIDA (Hall and Whitfield) 



Plate 16, figs. 4-7 



Crcpicephalus (Loganellus) nitidus Hall and Whitfield, 1877, U. S. Geol. 



Expl. 40th Paral., Vol. 4, p. 212, pi. 2, figs. 8-10. (Original description 



and illustrations.) 

 Ptychoparia nitidus Walcott, 1884, Monogr. U. S. Geol. Surv., Vol. 8, p. 57. 

 Dunderbergia nitida Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, 



p. 56, pi. II, fig. 2. 



There is nothing to be added to the original description. 

 Formation and locality. — Upper Cambrian : Secret Canyon shale : 

 (61) Adams Hill. South of Hamburg- Mine, Eureka District, Nevada. 



Genus ELKIA Walcott 



Elkia Walcott, 1924, .Smithsonian Misc. Coll., Vol. 75, No. 2, p. 56. 



Description. — The outstanding characters of Elkia are the very 

 narrow, fixed cheeks together with the extended frontal limb. Gla- 

 bella large, convex, outlined all around and shghtly tapering : ■ occipi- 

 tal furrow narrow and deeply impressed. There is one pair of gla- 

 bellar furrows which bend backward but very slightly and do not 

 unite across the middle ; by turning some specimens carefully in the 

 light additional faintly defined anterior pairs nmy be seen. 



The eyes are beneath a large and apparently flattened palpebral 

 lobe. None of the specimens is well preserved in this area due to 

 the fact that the fixed cheeks stand nearly vertical and are quite 

 easily broken away. The shape and size of the postero-lateral limbs 

 are also unknown. 



The facial sutures diverge in passing forward and then converge 

 to the median line of the head, thus outlining an unusual triangular 

 frontal limb, separated by a very slight, transverse furrow from a 

 narrow frontal limb. Remaining parts unknov/n. 



Genotype. — DiccllocepJialus nasntus Walcott. 



Range. — Upper Cambrian : Eureka District, Nevada. 



ELKIA NASUTA (Walcott) 



Plate 18, figs. 1-3 



Dicclloccphalus nasutus Walcott, 1884, Monogr. U. S. Geol. Surv., Vol. 8, 

 p. 40, pi. 10, fig. 15. (Original description and illustration.) Matthew, 

 1893, Trans. Roy. Soc. Canada, Vol. 10, sec. 4, p. 11, footnote. 



Proampyx nasutus Walcott, 1914, Smithsonian Misc. Coll., Vol. 57, No. 13, 

 p. 352. (Refers species to Proampy.v.) 



Elkia nasuta Walcott, 1924, Smithsonian Misc. Coll., Vol. 75, No. 2, p. 56, 

 pi. 10, fig. 8. 



The original description includes what is known of the species, no 

 new material being available. 



