NO. 3 UPPER CAMBRIAN TRILOBITE FAUNAS — RASETTI 45 



stone member of the Nolichucky {Crepicephalus zone) at locality 

 cnm/2. 



Types.— Coiy^QS : U.S.N.M. 94885. Plesiotype : U.S.N.M. 144563. 



Family CREPICEPHALIDAE Kobayashi, 1935 



Genus CREPICEPHALUS Owen, 1852 



Type species. — Dikelocephalus ? iowensis Owen. 



CREPICEPHALUS of. C. SCISSILIS Resser 



Plate 8, figure 30 



Crepicephalus scissilis Resser, 1938a, p. 72, pi. 11, figs. 34, 35. 

 Crepicephalus greendalensis Resser, 1938a, p. 7Z, pi. 11, figs. 46, 47. 



A few, exfoliated pygidia resemble this species in the general shape, 

 differing in the following minor features. The outline between the 

 spines is slightly concave rather than straight; the median profile of 

 the pleural region behind the axis is somewhat concave, instead of 

 convex as it appears in Resser's specimens. Possibly these differences 

 should be attributed specific value when better-preserved and more 

 complete material can be found. 



Occurrence. — Type locality for C. scissilis is U.S.N.M. 124a, 4 miles 

 NE. of Rogersville. Type locality for C. greendalensis is U.S.N.M. 

 36u, near Greendale, Va. The author's material was collected from the 

 uppermost beds of the lower limestone member of the Nolichucky 

 {Crepicephalus zone) at locality cnn/3. 



Disposition of material. — Figured specimen : U.S.N.M. 144564. 



CREPICEPHALUS BUTTSI Resser 



Plate 6, figures 5, 6 



Crepicephalus buttsi Resser, 1938a, p. 72, pi. 11, figs. 28, 29, 49, SO. 

 Crepicephalus expansus Resser, 1938a, p. 75, pi. 11, fig. Z6. 



Crepicephalus buttsi is represented by cranidia and pygidia poorly 

 preserved and somewhat flattened in shale, while C. expansus is based 

 on a limestone pygidium. No observable differences separate the pygi- 

 dia bearing the two names. A form collected by the author and repre- 

 sented only by pygidia is identified with this species. The individual 

 specimens vary to some extent in possessing straight or somewhat in- 

 ward curved spines. Since both types occur in the same bed, these slight 

 differences are not attributed specific significance. 



Occurrence. — The type locality of C. buttsi is U.S.N.M. 26s, near 

 Cleveland, Va. The type locality of C. expansus is U.S.N.M. 105, near 

 Sneedville, Hancock County, Tenn. The specimens figured herein are 

 from locality cnn/19. 



